For a long time, I considered adding a mattress. To retain the visual pleasure of the exposed matrix I experimented with various kinds of translucent padding. Nothing adequately retained the sensation of the pegs.
Foams, rubbers, and various other materials were attempted.
Various other dead ends followed. I 3D printed three-part molds, I CNC milled two-part molds from MDF, and finally I hand turned positives on the lathe and created silicone mother molds, into which the pegs could be poured.