Press see inside and there are a bunch of custom blocks you can use. Press the green flag to see an example of what it can do. The color and transparency are a range of 0 to 255. For transparency, lower is more transparent.
So Far, I've got a Block for: Lines Rectangles Circles Stars Set Pen Color to (R) (G) (B) Transparency to (A) I'm Working on Blocks for: Ellipse
