A point carries position (x,y) and an angle α. The ray through the point meets the axes at anchors that store extra structure.
1.00×
0.00
0.00 rad
160
point
angles
x-axis anchor
y-axis anchor
Drag the bright point to change (x,y). Drag the golden handle to rotate α. When z→α is active, the third coordinate bends the angle and shifts the axis anchors.