This material is well suited for wearables, cosplay, and e-textiles, and more. One exciting way to see the heat spread across your conductive fabric is with heat-reactive paint!
Thermochromic pigments change color when exposed to temperature changes. Pigments come with different temperature ratings, for this application you'll want to look for pigments that are static at room temperature and change when heat is applied (as opposed to cold).
For all of the examples in this guide, I used heat activated 86F pigment from Solar Color Dust. The pigment can be mixed with textile medium or ModPodge. If your textile medium is thin, you'll be able to mix in more pigment for denser color without making your fabric too stiff. Experiment with ratios until you get the effect you want.
After painting your fabric with the thermo-reactive paint, let the fabric dry completely before applying heat to see the color change. In some cases, the pigments can get "stuck" on one color if you apply too much heat while they are drying. If you want to cut down drying time, use a fan to blow cool air over the painted fabric.