width:
height:
grid:

overdraw:

BG
Color1
Color2
Color3

click three points to draw a thing:

triangle (3 corners)
all triangles need to be right triangles
with two sides aligned to the grid
circle (center, inner rad, outer rad)
ellipse (like circle but stretches with image ratio)
band (2 points of one side, thickness)

full circle/ellipse
half circle/ellipse (clockwise)
quarter circle/ellipse (clockwise)