HOWTO: Triangular shape pattern with mouse effect

What I want to achieve is the following: Build a pattern like this or this and apply a mouseover effect.

The effect I want is a basic darken/lighten effect so that shapes will be 'pushed down'.

So my questions are:

1. What is the best way to make the pattern? I was thinking about using canvas, but maybe there is a better way?
2. How do I render the pattern? (Looking for a base code example as a starting point)
3. How do I implement the mouse effect?

Thanks!