This is what I use for markup so I don't get lost in the sea of buttons on my 256. The beads are off a €2 candle decoration and they are tied to plain sewing thread that I spun around a bit to get it to stay together, and then tied knots at the ends to keep the beads in their place.

It's not perfect - every now and then I accidentally touch a wire and it goes out of position. It works better than I feared though, good enough to be usable. When the threads go out of position it's easy enough to put them back, even when under the stress of live performance.