The posts on this blog that have talked about Pascal's Triangle have all used diagrams drawn with TinkerPlots. Aside from its value as educational software, TP is good for drawing diagrams like these (and others, like the polygonal number diagrams described here) that are derived from calculations.
A TinkerPlots document that can draw these diagrams is found here. The images at the top of the post were created with this document, and show some of the modular patterns in Pascal's triangle (for mod 2 and mod 7).
