The stroke shape is the basic shape of each stroke stamp, including its size, edge softness, aspect, angle, and whether or not its round or square.

Square toggles the stamp between a round and a square shape.

Size sets the default size of the stroke. This can be adjusted each time you draw by changing the size in the Stroke panel.

Edge determines how wide in pixels the "soft" area of the edge is.

Aspect adjusts the shape of the stroke tip-from a circle to an oval in the case of a round tip, and from a square to a line in the case of a square tip.

Angle sets the angle of the stroke tip. Used in conjunction with Aspect, this is a common way to create a calligraphic-type stroke.