I tried my hand at making a calculator with this; managed to make one that could do addition, subtraction, multiplication, and integer division with both positive and negative numbers. There doesn't seem to be a good way to share programs (rulesets?) made with this, so I stitched some screenshots together to show it all in an image. I changed four of the symbols into the four operators for convenience.
First operand is a quantity of triangles, second operand is a quantity of diamonds (black for positive, white for negative). You perform an operation by placing an operator symbol in the bag with the operands and evaluate until it stops.
The ruleset takes up all 48 rule slots. I imagine the same functionality could probably be done with less rules and less symbols, but it's hard to keep track of it all and not have it interfere with itself so I didn't bother. I'm proud of it nonetheless.