For example, given the arrays [1,2] and [1,2,3,4], produce this array: [2,3,4,5,3,4,5,6].

In Python, this would look like this:

a = [1,2]
b = [1,2,3,4]
c = []
for x in a:
	for y in b:
		c.append( x + y )
		
print c
#  [2, 3, 4, 5, 3, 4, 5, 6]

In ICE, one way to do this would be to add
[1,1,1,1,2,2,2,2]
to
[1,2,3,4,1,2,3,4]

Here’s an ICE tree that does just that:

This ICE tree uses the modulo trick, and the scalar-to-integer truncation trick.

You can see a variation of this in this Softimage mailing list post..

I was hoping to do something more complicated, but I ran out of time…

Here’s the exercise: Take an array and build a new array by adding consecutive elements in the original array.
For example, given this array:

1 3 2 4 7 5 6 9 11 1 3 9

construct this array:

1+3, 3+2, 2+4, 4+7, ..., 3+9

Summing up three consecutive elements will hopefully be more interesting…

Here’s an ICE tree that removes all duplicate values from an array of integers, leaving you with an array of unique integer values: