Here’s a relatively simple ICE tree that arranges hexagons on the XZ plane. The “difficult” part was creating the arrays of position coordinates. For that I used the standard modulo technique. It’s funny, it all makes perfect sense when you’re plugging stuff together, but afterwards it’s hard to make heads or tail of what you did 🙂

To understand what’s going on here, it helps to look at the final arrays that are built:

The math for arranging the hexagon tiles is pretty simple. I started with a simple test point cloud to make sure I understood what I needed to do. After that, it was just a question of setting up the arrays.

If you want to take a look at the ICE trees, here’s some compounds. Note that this isn’t a finished piece of work. It’s more of a draft version. For example, my hexagon has a side length of 5 and that’s hardcoded into the ICE tree right now.
Hexagon_Tiler.xsicompound
Hexagon_Math_Tester.xsicompound