Visualization Types Codex

1
DESIGN + VISUAL THINKING V. 0.5-B BY PETER STOYKO THE CHALLENGE Complex systems are difficult to understand without the aid of visuals. There are too many moving parts to mentally keep track of. The parts interact in too many ways. The whole system is cognitively overwhelming insofar as it cannot be absorbed in one go without the aid of an external reference. That is partly due to humans' inability to juggle more than a few complicated ideas in working memory at one time. Thus, visuals are a simplifying and organizing device that complements the way human naturally think if they are designed well. This poster is an early glimpse of a larger project (called SystemViz) that explores what it means to design such visuals well. TAKING STOCK OF VISUAL METHODS. The first challenge is that there are many ways to display systems visually. Diagram formats and notations have proliferated. Some correspond to particular disciplines or tasks. Each has innumerable minor variations. It is worth taking stock of these "visual vocabularies" because the choice of visualization method skews the way systems are understood. Different methods emphasize different things and removes certain details from the picture: all are, by definition, a form of reductionism; all contain implicit assumptions about what a system is and how it behaves. For example, one method may depict systems as stocks and flows, another may depict them as logical sequences; another as causes, effects, and two-way dynamics; another as signals and boundaries. These differences depend on the underlying theory in use, but also the unthinking tendency to adopt a visualization method out of convenience or habit. The result is a paradox: without visuals to help model systems, understanding is limited; visual conventions frame the way systems are understood, which can undermine understanding. Thus, the first task of this project is to provide an inventory of the various visualization methods by grouping them according to their main points of differentiation. This is a first approximation. The aim is to solicit feedback about this way of organizing visuals and determining if there are major errors of omission. The aim is also to have a discussion of the biases and blind spots of the respective methods. IDENTIFYING MISSING CONCEPTS. There are many systems concepts that are applicable across practical and academic disciplines. The overall literature is wide and deep. Some concepts are wide recognized; others less so, partly because of a lack of trans-disciplinary engagement. That presents an opportunity for visuals to act as an interdisciplinary lingua franca. That also raises some important questions: What systems concepts are not easily depicted using conventional methods of visualization? Identifying these concepts is the second aim of the project. The hope is to start a conversation about visualization methods that might fill these glaring omissions. EXPLORING VISUALIZATION CHALLENGES. Creating an inventory is an opportunity to reflect on recurring problems and trade- offs. That is the third task of the project. The goal is to provoke a discussion about ways of overcoming these difficulties. A few lessons from the discipline of information design provide partial guidance. The ultimate goal is to turn these stock-taking exercises and "guide posts" and turn them into a design and teaching tool (a "codex") in an appealing and accessible form. This post is an early step in that direction. Inspiration is drawn from David Garcia's Manual of Architectural Possibilities series of road- map-like foldable posters. Interactive, screen-based versions may also emerge. If the project yields some interesting techniques, the goal is to make those openly available to members of the larger community interested in systems thinking. Peter Stoyko is an interdisciplinary social science and information designer at Elanica, a management consultancy that specializes in service design and governance. Feel free to contact him at [email protected] or visit the project page at systemviz.elanica.com. ? NO-NAME CONNECTIONS Unspecified links between items make relations and dynamics ambiguous, often suggesting analytical evasion. Link labels, badges, symbolic ends, or encodings (e.g. color coding) indicate nature of link. // FIX // VISUALIZATIONHURDLES VISUALIZATIONTYPES SPAGHETTI TANGLE Unmanageable links between objects makes it difficult to distinguish relationships. Prioritize and differentiate lines. Use layering techniques. Add visual affordances to guide the eye. // PARTIAL FIX // STATE EXPLOSION Unmanageable numbers of diagram nodes, especially for number of potential states in Petri nets. Increase level of abstraction at the cost of precision. Use different levels of analysis for crucial details. // TRADE-OFF // EVERYTHING CONNECTED The temptation to connect everything to everything else because, at some level, a relation can be imagined. Rank and differentiate relationships according to well articulated analytical priorities. // FIX // FALSE EQUIVALENCE Failure to sufficiently differentiate linkages creates mistaken impression of equal importance. Differentiate lines in ways that convey magnitude and qualitative differences. Add text labels and numerical weights. // FIX // NOTATION OVERLOAD Number of symbols and distinctions exceeds viewer's ability to differen- tiate and juggle in working memory. Reduce number of encodings, especially for minor distinctions. Do not rely on legends. // PARTIAL FIX // PERCEPTUAL SIMILARITY Basic shapes used in diagram are not sufficiently differentiated so that important distinctions are overlooked. Use shapes (and other encodings, such as color and text style) with higher levels of contrast. // FIX // ETHNOCENTRIC SYMBOLISM Symbolic visual objects (such as icons) carry cultural meanings that are not universally understood. Research cultural background of symbols. Use symbols recognizable across cultures. // PARTIAL FIX // SUBJECT MISMATCH Diagram method is poor fit to the nature of the subject matter because of mismatched theory of use. Use more suitable method. Abandon highly standardized notation for more bespoke graphics. // FIX // NEGLECTEDCONCEPTS? A C E E L J J Z A M C 4 5 6 7 M 4 5 6 Perforated Collection Tube Fresh Water Reverse Osmosis Membrane Pressure Vessel Concentrate Fresh Water Feed Water Fresh Water LINKS BETWEEN OBJECTS SHOWING CAUSAL DIRECTION, MOVEMENT, OR SEQUENCE FLOW TRANSITION PETRI NETS AND OTHER MATHEMATICAL GRAPHIC NOTATIONS SHOW SYSTEM PHASES WITH PRECISION LOOP STOCKS, FLOWS, AND SYSTEM DYNAMICS ARE MAPPED AS LOOPS SITUATE SYSTEM DIAGRAMS ARE LAYERED OVER MAPS OF PHYSICAL SPACE AND OTHER DIAGRAMS ARRANGE NODES AND LINKS ARE ARRANGED AND CATEGORIZED WITH VARIOUS SPATIAL ARRANGEMENTS EXPLAIN ILLUSTRATED DIAGRAMS SHOWS HOW A SYSTEM WORKS BY MIMICKING REAL-WORLD APPEARANCE Geothermal Heat Magma Condenser Steam Hot Air & Water Vapor Waste Water Groundwater Replenishment Top-up Injection Well Production Well Impermeable Rock Cooling Water Impermeable Rock Conductive Rock Conductive Rock Groundwater Infiltration High Lands Water Run-off Warmed Water Cooling Water Power Transmission Power Generation Power Transmission Rain Water Coastal Winds Pump Turbine Generator Water Treatment Cooling Tower Households Transformer Condensate Heated Aquifer LIKEN VISUAL ANALOGIES COMPARE SYSTEMS TO OTHER SYSTEMS THROUGH BLENDING EXPOSE PART AND WHOLE RELATIONSHIPS OF SYSTEM ARE SHOWN REALISTICALLY THROUGH CUT-AWAY AND EXPLODED VIEWS YES NO NO Motion detected Animal? Human? Guard? Isolate Individual Remove Individual Escort to Office Send to Office On Duty? Machine? Beacon? Alone? Record Number Valid? Danger? Isolate Machine Escort to Lab Guard Check Continue monitoring YES NO NO NO NO YES YES YES YES NO NO YES NO YES YES Report Incident Input Reason Sound alarm Remove Machine GENERIC NOTATION PROCESS DECISION DELAY PROCESS FLOW TERMINAL DATA PROCESS GROUP DISPLAY MANUAL INPUT TRANSFER MANUAL LOOP LOOP LIMIT CONDITION ORGANIZATION PREPARATION STORED DATA DOCUMENT PARALLEL MODE SUB-PROCESS CONNECT SORT MERGE COMMENT AND Text CHECK COLLATE TO PAGE OR JUMP REFERNCE Intelligence Gathering Product Specifications Prototype Refine User Testing Tester Screening Test-site Preparation Outreach Implement Participant Recruitment Data Requirements Field Research Findings Reviewed Advisory Review Study Prepared Finalization Client Needs Assessment Client Feedback Stakeholder Mapping Product Launch Participatory Research R1 Integrative Learning B1 Product Development R2 Knowledge Mobilization R3 Iteration R1b Iteration R2b Testing R3c Tweak R2c ( Arita, 49 ) ( Ito, 21 ) ( Nishi, 31 ) ( Fukuyama, 42 ) ( Takeuchi, 38 ) ( Enomoto, 26 ) ( Sakoda, 55 ) Request End Submission Process Flag Expedited Submission References Checked Record Ready Request Routed Request Filed Record Reviewed Add More References Process ( Matsuki, 22 ) CAUSAL LINK POSITIVE EFFECT DYNAMIC LINK NEGATIVE EFFECT LOOP LABEL BOUNDARY DELAYED EFFECT FLOW OUTFLOW BIFLOW A2 BALANCED LOOP (OR ) B REINFORCING LOOP (OR ) R FLOW RATE OR OR GENERIC NOTATION STATE STATUS OF SYSTEM ITEM PSEUDO STATE EXOGENOUS STATE SEE SCHOLARPEDIA ARTICLE INSERT TRANSITION CHANGE TO NEW STATE SUBSYSTEM MULTIPLE PARTS TO STATE OR TRANSITION DELAY IN NUMBER OF TIME UNITS TIME STAMP START OF MOVE IN TIME UNITS TOKENS OBJECT MOVING THROUGH SYSTEM TOKEN LABEL DATA SEPARATED BY COMMA @+3 3 GENERIC NOTATION MULTIPLE LAYERS LAYERED LEVELS OF ANALYSIS EXPLODED CUT AWAY THE FOLLOWING ARE SOME EXAMPLES OF SYSTEM CONCEPTS THAT ARE BEING COLLECTED AS PART OF THE PROJECT TO SEE IF EXISTING VISUALIZATION METHODS CAN ADEQUATE- LY REPRESENT THEM. CURRENTLY, THE DATABASE HAS APPROXIMATELY A HUNDRED ITEMS GATHERED FROM ACROSS NATURAL AND SOCIAL SCIENTIFIC DISCIPLINES. ATTRACTOR An element that draws others towards it or distorts its trajectory through an attractive force. REPELLER An element that pushes others away or distorts its trajectory through repelling force. SIDE EFFECTS Externalities or unanticipated consequences caused by a force or dynamic between two objects. DISTAL DRIVER A background cause observ- able at a high level of analysis ("bigger picture"); a diffuse factor acting on more obvious factors in a causal chain. KLUDGE A make-shift work-around to cope with an immediate problem, adding variation (often complexity) to system; source of "jagaad" innovation. ENABLER A factor that gives another factor a boost, either as a necessary ingredient or as a contributing one. PROXIMATE DRIVER A variable that directly causes another variable to change; that is, an immediate cause. FRICTION A factor that impedes another factor directly to blunt, delay, or skew. An obstacle that prevents a variable from running its course by affecting other variables in a causal chain PROTECTOR A blocker that preserves the state of a variable from some or all outside influences Boundaries Signals CONTAINER A boundary that groups items discretely by separating them from others SEPARATOR A boundary that separates or differentiates two groups or areas SEMI-PERMEABLE A boundary that blocks certain factors but not others depending on their qualities BOTTLENECK A boundary that limits the throughput of forces through an area or process DIVERSITY BETWEEN The variation between different categories of object DIVERSITY WITHIN The amount and quality of variation found within a single category of object Factor that has to be present for one thing to cause another to change, perhaps part of the environment PERSPECTIVE How the system changes depending on the vantage point or qualities of the viewer. SENSING Parts of the system that receive signals from the external environment or elsewhere in the system. INPUT/OUTPUT Parts of the system that take in or expel factors from the outside. COMPATIBILITIES Aspects of a system that are able to interact functionally or to mutual benefit because of compatible design features PARASITE An outside agent that derives benefit from an host or system while imposing costs Relations Domains Forces PROCESS CONCEPT DATABASE Sort Store Store Form Status No Merge New? B A A X B Sort Start Sort Pump X Archive Activity Match Report Inspect Soya G H J L K A M N F Water Land Market Soil Sun C G C2 P2 P1 C3 G2 J1 K1 P A B M2

Transcript of Visualization Types Codex

D E S I G N + V I S U A L T H I N K I N G

V . 0 . 5 - B B Y P E T E R S T O Y K O

THE CHALLENGEComplex systems are difficult to understand without the aid of visuals. There are too many moving parts to mentally keep track of. The parts interact in too many ways. The whole system is cognitively overwhelming insofar as it cannot be absorbed in one go without the aid of an external reference. That is partly due to humans' inability to juggle more than a few complicated ideas in working memory at one time. Thus, visuals are a simplifying and organizing device that complements the way human naturally think if they are designed well. This poster is an early glimpse of a larger project (called SystemViz) that explores what it means to design such visuals well.

TAKING STOCK OF VISUAL METHODS. The first challenge is that there are many ways to display systems visually. Diagram formats and notations have proliferated. Some correspond to particular disciplines or tasks. Each has innumerable minor variations. It is worth taking stock of these

"visual vocabularies" because the choice of visualization method skews the way systems are understood. Different methods emphasize different things and removes certain details from the picture: all are, by definition, a form of reductionism; all contain implicit assumptions about what a system is and how it behaves. For example, one method may depict systems as stocks and flows, another may depict them as logical sequences; another as causes, effects, and two-way dynamics; another as signals and boundaries. These differences depend on the underlying theory in use, but also the unthinking tendency to adopt a visualization method out of convenience or habit. The result is a paradox: without visuals to help model systems, understanding is limited; visual conventions frame the way systems are understood, which can undermine understanding. Thus, the first task of this project is to provide an inventory of the various visualization methods by grouping them according to their main points of differentiation. This is a first approximation. The aim is to solicit feedback about this way of organizing visuals and determining if there are major errors of omission. The aim is also to have a discussion of the biases and blind spots of the respective methods.

IDENTIFYING MISSING CONCEPTS. There are many systems concepts that are applicable across practical and academic disciplines. The overall literature is wide and deep. Some concepts are wide recognized; others less so, partly because of a lack of trans-disciplinary

engagement. That presents an opportunity for visuals to act as an interdisciplinary lingua franca. That also raises some important questions: What systems concepts are not easily depicted using conventional methods of visualization? Identifying these concepts is the second aim of the project. The hope is to start a conversation about visualization methods that might fill these glaring omissions.

EXPLORING VISUALIZATION CHALLENGES. Creating an inventory is an opportunity to reflect on recurring problems and trade-offs. That is the third task of the project. The goal is to provoke a discussion about ways of overcoming these difficulties. A few lessons from the discipline of

information design provide partial guidance. The ultimate goal is to turn these stock-taking exercises and "guide posts" and turn them into a design and teaching tool (a "codex") in an appealing and accessible form. This post is an early step in that direction. Inspiration is drawn from David Garcia's Manual of Architectural Possibilities series of road-map-like foldable posters. Interactive, screen-based versions may also emerge. If the project yields some interesting techniques, the goal is to make those openly available to members of the larger community interested in systems thinking.

Peter Stoyko is an interdisciplinary social science and information designer at Elanica, a management consultancy that specializes in service design and governance.

Feel free to contact him at [email protected] or visit the project page at systemviz.elanica.com.

?NO-NAME CONNECTIONSUnspecified links between items make relations and dynamics ambig uous, often suggesting analytical evasion.

Link labels, badges, symbolic ends, or encodings (e.g. color coding) indicate nature of link.

// FIX //

VISUALIZATIONHURDLES

VISUALIZATIONTYPES

SPAGHETTI TANGLEUnmanageable links between objects makes it difficult to distinguish relationships.

Prioritize and differentiate lines. Use layering techniques. Add visual affordances to guide the eye.

// PARTIAL FIX //

STATE EXPLOSIONUnmanageable numbers of diagram nodes, especially for number of potential states in Petri nets.

Increase level of abstraction at the cost of precision. Use different levels of analysis for crucial details.

// TRADE-OFF //

EVERYTHING CONNECTEDThe temptation to connect everything to everything else because, at some level, a relation can be imagined.

Rank and differentiate relationships according to well articulated analytical priorities.

// FIX //

FALSE EQUIVALENCEFailure to sufficiently differentiate linkages creates mistaken impression of equal importance.

Differentiate lines in ways that convey magnitude and qualitative differences. Add text labels and numerical weights.

// FIX //

NOTATION OVERLOADNumber of symbols and distinctions exceeds viewer's ability to differen-tiate and juggle in working memory.

Reduce number of encodings, especially for minor distinctions. Do not rely on legends.

// PARTIAL FIX //

PERCEPTUAL SIMILARITYBasic shapes used in diagram are not sufficiently differentiated so that important distinctions are overlooked.

Use shapes (and other encodings, such as color and text style) with higher levels of contrast.

// FIX //

ETHNOCENTRIC SYMBOLISMSymbolic visual objects (such as icons) carry cultural meanings that are not universally understood.

Research cultural background of symbols. Use symbols recognizable across cultures.

// PARTIAL FIX //

SUBJECT MISMATCHDiagram method is poor fit to the nature of the subject matter because of mismatched theory of use.

Use more suitable method. Abandon highly standardized notation for more bespoke graphics.

// FIX //

NEGLECTEDCONCEPTS?

A

C

E

E

L

J

J

Z

A

M

C

4

5

6

7

M

45

6

Perforated Collection Tube

Fresh Water

Reverse Osmosis Membrane

Pressure Vessel

Concentrate

FreshWater

FeedWater

FreshWater

LINKS BETWEEN OBJECTS SHOWING CAUSAL DIRECTION, MOVEMENT, OR SEQUENCE

FLOW TRANSITIONPETRI NETS AND OTHER MATHEMATICAL GRAPHIC NOTATIONS SHOW SYSTEM PHASES WITH PRECISION

LOOPSTOCKS, FLOWS, AND SYSTEM DYNAMICS ARE MAPPED AS LOOPS

SITUATESYSTEM DIAGRAMS ARE LAYERED OVER MAPS OF PHYSICAL SPACE AND OTHER DIAGRAMS

ARRANGENODES AND LINKS ARE ARRANGED AND CATEGORIZED WITH VARIOUS SPATIAL ARRANGEMENTS

EXPLAINILLUSTRATED DIAGRAMS SHOWS HOW A SYSTEM WORKS BY MIMICKING REAL-WORLD APPEARANCE

Geothermal Heat

Magma

Condenser

Steam

Hot Air &Water Vapor

Waste Water

GroundwaterReplenishment

Top-up

InjectionWell

ProductionWell

Impermeable Rock

Cooling Water

Impermeable Rock

Conductive RockConductive Rock

GroundwaterInfiltration

High Lands

WaterRun-off

Warmed Water

CoolingWater

PowerTransmission

Power GenerationPower

Transmission

Rain Water

Coastal Winds

Pump

Turbine

GeneratorWater

Treatment

CoolingTower

Households

Transformer

Condensate

Heated Aquifer

LIKENVISUAL ANALOGIES COMPARE SYSTEMS TO OTHER SYSTEMS THROUGH BLENDING

EXPOSEPART AND WHOLE RELATIONSHIPS OF SYSTEM ARE SHOWN REALISTICALLY THROUGH CUT-AWAY AND EXPLODED VIEWS

YES

NO

NO

Motiondetected Animal?

Human?

Guard?

IsolateIndividual

RemoveIndividual

Escort toOffice

Send toOffice

On Duty?

Machine?

Beacon? Alone?RecordNumber

Valid?

Danger?

IsolateMachine

Escortto Lab

GuardCheck

Continuemonitoring

YES

NO

NO

NO

NO

YES

YES

YES

YES

NO NO

YES

NO

YES

YES

ReportIncident

InputReason

Soundalarm

RemoveMachine

G E N E R I C N O T A T I O N

PROCESS

DECISION

DELAY

PROCESS FLOW

TERMINAL

DATA

PROCESS GROUP

DISPLAY

MANUAL INPUT

TRANSFER

MANUAL LOOP

LOOP LIMIT

CONDITION

ORGANIZATION

PREPARATION

STORED DATA

DOCUMENT

PARALLEL MODE

SUB-PROCESS

CONNECT

SORT

MERGE

COMMENT

AND

Text

CHECK

COLLATE

TO PAGE

OR

JUMPREFERNCE

IntelligenceGathering

ProductSpecifications

Prototype

Refine

UserTesting

TesterScreening

Test-sitePreparation

Outreach

Implement

ParticipantRecruitment

DataRequirements

FieldResearch

FindingsReviewed

AdvisoryReview

StudyPrepared

Finalization

Client NeedsAssessment

ClientFeedback

StakeholderMapping

ProductLaunch

ParticipatoryResearch

R1

IntegrativeLearning

B1

ProductDevelopment

R2

KnowledgeMobilization

R3

Iteration

R1b

Iteration

R2b

Testing

R3c

Tweak

R2c

( Arita, 49 )

( Ito, 21 )

( Nishi, 31 )

( Fukuyama, 42 )

( Takeuchi, 38 )

( Enomoto, 26 )

( Sakoda, 55 )

Request End

Submission

Process

Flag

ExpeditedSubmission

ReferencesChecked

Record Ready

RequestRouted

RequestFiled

RecordReviewed

Add MoreReferences

Process

( Matsuki, 22 )

CAUSALLINK

POSITIVEEFFECT

DYNAMICLINK

NEGATIVEEFFECT

LOOPLABEL

BOUNDARY

DELAYEDEFFECT

FLOW

OUTFLOW

BIFLOW

A2

BALANCEDLOOP(OR ) B

REINFORCINGLOOP(OR ) R

FLOWRATE

OR

OR

G E N E R I C N O T A T I O N

STATESTATUS OFSYSTEM ITEM

PSEUDO STATEEXOGENOUSSTATE

SEE SCHOLARPEDIA ARTICLEINSERT

TRANSITIONCHANGE TONEW STATE

SUBSYSTEM MULTIPLE PARTSTO STATE ORTRANSITION

DELAYIN NUMBER OFTIME UNITS

TIME STAMP START OF MOVEIN TIME UNITS

TOKENS OBJECT MOVINGTHROUGH SYSTEM

TOKEN LABELDATA SEPARATEDBY COMMA

@+3

3

G E N E R I C N O T A T I O N

M U LT I P L E L A Y E R S

L A Y E R E D L E V E L S O F A N A LY S I S

E X P L O D E D

C U T A W A Y

THE FOLLOWING ARE SOME EXAMPLES OF SYSTEM CONCEPTS THAT ARE BEING COLLECTED AS PART OF THE PROJECT TO SEE IF EXISTING VISUALIZATION METHODS CAN ADEQUATE-LY REPRESENT THEM. CURRENTLY, THE DATABASE HAS APPROXIMATELY A HUNDRED ITEMS GATHERED FROM ACROSS NATURAL AND SOCIAL SCIENTIFIC DISCIPLINES.

ATTRACTORAn element that draws others towards it or distorts its trajectorythrough an attractive force.

REPELLERAn element that pushesothers away or distorts itstrajectory through repellingforce.

SIDE EFFECTSExternalities or unanticipated consequences caused bya force or dynamic betweentwo objects.

DISTAL DRIVERA background cause observ-able at a high level of analysis ("bigger picture"); a diffuse factor acting on more obvious factors in a causal chain.

KLUDGEA make-shift work-around to cope with an immediate problem, adding variation (often complexity) to system; source of "jagaad" innovation.

ENABLERA factor that gives another factor a boost, either as a necessary ingredient or as a contributing one.

PROXIMATE DRIVERA variable that directly causes another variable to change; that is, an immediatecause.

FRICTIONA factor that impedes another factor directly toblunt, delay, or skew.

An obstacle that prevents a variable from running its course by affecting other variables in a causal chain

PROTECTORA blocker that preserves the state of a variable from some or all outside influences

Boundaries SignalsCONTAINERA boundary that groupsitems discretely by separating them fromothers

SEPARATORA boundary that separatesor differentiates twogroups or areas

SEMI-PERMEABLEA boundary that blocks certain factors but notothers depending on theirqualities

BOTTLENECKA boundary that limits thethroughput of forcesthrough an area or process

DIVERSITY BETWEENThe variation between different categories of object

DIVERSITY WITHINThe amount and quality of variation found within a singlecategory of object

Factor that has to be present for one thing to cause another to change, perhaps part of the environment

PERSPECTIVEHow the system changes depending on the vantage point or qualities of the viewer.

SENSINGParts of the system that receive signals from the external environment or elsewhere in the system.

INPUT/OUTPUTParts of the system that take in or expel factors from the outside.

COMPATIBILITIESAspects of a system that areable to interact functionallyor to mutual benefit becauseof compatible design features

PARASITEAn outside agent that derives benefit from an host or system while imposing costs

Relations DomainsForces

PROCESSCONCEPT DATABASE

Sort

Store

Store

Form

Status

No MergeNew?

BA

AX

B

Sort

Start

Sort

Pump

X

Archive

Activity

Match

Report

InspectSoya

G

HJ

L

K

AM

N

F

Water

Land

Market

Soil

Sun

C

G1

C2

P2

P1

C3

G2J1K1

2

J2

PA

B

M2