Here is the simplest Combinatorial Ladder game mode, which does not have any negative values and is not circular.
Please find the code for this program on my github page.
Directions:
Click to add a rung.
Click on an existing rung inside shaded area to delete.
Click and drag on any rung to move it.
Click "+" to restart and add a rail.
Click "-" to restart and subtract a rail.
Click "o" to restart.