This is really just an extension of the excellent xyslider by LiamG at: https://forum.pdpatchrepo.info/topic/8656/xy-slider-controls-two-variables-at-once
I really love your slider and have used it for years.
So first want to thank you for the great work on it.
And 2nd, hope you don't mind....I took the liberty and added a 3rd dimenstion (z) via the mouse scrollwheel and a resizing canvas, as shown in the following:
p.s. one additional change I made that I have used alot, is I added the parent level to the iemguts as a creation argument($6).
Peace. Thanks for sharing.