I assume you are talking about a less obscure app like Live, Bitwig, or FL Studio, but in case not: I vaguely remember a 90s Windows application (possibly shareware) that had a 3D pre-rendered UI with keys shown on screen that looked like a payphone's keypad. You could assign beatmatched loops and hits to any key and toggle or trigger them in a synchronized manner (either with the mouse of the physical keyboard). I had loads of fun as a kid recreating Music Instructor's archetypal/self-aware cliché dance song "Hymn" with it.
Do you or anyone else know which software I'm talking about?