Android api quirk number 5
Wow this is silly.
public void drawRect(float left, float top, float right, float bottom, Paint paint)
Usually it doesn't matter if top is higher than bottom. Either way a rectangle is drawn.
UNLESS, top is outside of the screen. Then no rectangle is drawn at all.
So you can have rectangles that are partially visible, but only if their top is greater than their bottom.
ZOMG that was a hard bug to figure out....