Predefined Shape Geometries
The Telerik Diagramming Framework provides three types of predefined shape geometries - ArrowShapes, CommonShapes and FlowChartShapes. For each of these types the framework exposes xaml markup extensions that can be applied at the RadDiagramShape.Geometry property as a shortcut way of creating a shape.
This article contains a list with the available geometries and shows how to set a geometry.
Create a geometry in code behind
Geometry arrowGeometry = ShapeFactory.GetShapeGeometry(ArrowShapeType.Arrow1);
diagramShape.Geometry = arrowGeometry;
ArrowShapes
Arrow1

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow1}" />
Arrow2

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow2}" />
Arrow3

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow3}" />
Arrow4

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow4}" />
Arrow5

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow5}"/>
Arrow6

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow6}" />
Arrow7

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow7}"/>
Arrow8

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=Arrow8}"/>
DoubleArrow1

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=DoubleArrow1}" />
DoubleArrow2

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=DoubleArrow2}" />
DoubleArrow3

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=DoubleArrow3}" />
DoubleArrow4

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=DoubleArrow4}" />
DoubleArrow5

<telerik:RadDiagramShape Geometry="{telerik:ArrowShape ShapeType=DoubleArrow5}" />
CommonShapes
CloudShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=CloudShape}" />
Cross2Shape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=Cross2Shape}"/>
CrossShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=CrossShape}" />
EllipseShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=EllipseShape}" />
HexagonShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=HexagonShape}"/>
OctagonShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=OctagonShape}" />
PentagonShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=PentagonShape}" />
RectangleShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=RectangleShape}"/>
RightTriangleShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=RightTriangleShape}" />
RoundedRectangleShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=RoundedRectangleShape}" />
Star5Shape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=Star5Shape}"/>
Star6Shape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=Star6Shape}" />
Star7Shape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=Star7Shape}" />
TriangleShape

<telerik:RadDiagramShape Geometry="{telerik:CommonShape ShapeType=TriangleShape}"/>
FlowChartShapes
BeginLoopShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=BeginLoopShape}" />
CardShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=CardShape}"/>
CollateShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=CollateShape}" />
CreateRequestShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=CreateRequestShape}" />
Database1Shape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=Database1Shape}"/>
Database2Shape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=Database2Shape}" />
Database3Shape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=Database3Shape}"/>
DataShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DataShape}" />
DataStoreShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DataStoreShape}" />
DecisionShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DecisionShape}"/>
DelayShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DelayShape}" />
DevidedProcessShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DevidedProcessShape}" />
DirectDataShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DirectDataShape}"/>
DisplayShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DisplayShape}" />
DocumentShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DocumentShape}" />
DuplicatingShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=DuplicatingShape}"/>
ExternalDataShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=ExternalDataShape}" />
FeedbackShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=FeedbackShape}" />
FramedRectangleShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=FramedRectangleShape}"/>
InternalStorageShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=InternalStorageShape}" />
LinedDocumentShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=LinedDocumentShape}" />
LoopLimitShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=LoopLimitShape}"/>
ManualInputShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=ManualInputShape}" />
ManualOperationShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=ManualOperationShape}" />
MessageFromUserShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=MessageFromUserShape}"/>
MessageToUserShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=MessageToUserShape}" />
MicroformProcessingShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=MicroformProcessingShape}" />
MicroformRecordingShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=MicroformRecordingShape}"/>
MultipleDocumentShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=MultipleDocumentShape}" />
OffPageConnectionShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=OffPageConnectionShape}" />
OffPageLinkShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=OffPageLinkShape}"/>
OffPageReflectionShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=OffPageReflectionShape}" />
OrShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=OrShape}" />
PaperTapeShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=PaperTapeShape}"/>
PredefinedShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=PredefinedShape}" />
PreparationShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=PreparationShape}" />
PrimitiveFromCallShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=PrimitiveFromCallShape}"/>
PrimitiveToCallShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=PrimitiveToCallShape}" />
SequentialDataShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=SequentialDataShape}" />
SortShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=SortShape}"/>
StartShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=StartShape}" />
StoredDataShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=StoredDataShape}" />
SummingJunctionShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=SummingJunctionShape}"/>
TerminatorShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=TerminatorShape}" />
TransmittalTapeShape

<telerik:RadDiagramShape Geometry="{telerik:FlowChartShape ShapeType=TransmittalTapeShape}" />