Hi, I've been experimenting with gradients and buttons, and I want to have a button that switches between a set of gradients, but I am not sure how. Any ideas?

I have been looking at the temperature of my Macbook Air lately, and I notice that it is in the 110-130's even while performing simple tasks. Despite the seemingly high temperature, the CPU load is still below 20% when this happens, so it may be nothing, but I just want to make sure nothing is wrong