Temperature distribution on 2d surface

It’s been a while since I thought about modeling heat distribution on 2d surfaces. After doing same thing for 1d strings in Excel, making this thing work on programm language, writing some code and getting it to work seemed almost impossible. However, it wasn’t that hard tho, just had a lot of struggles In this examples I’m using finite difference method, to approximate second order equation in patrial derivatives (Fourier equation). Boundary conditions can be any of 4 types - izolated side, set temperature, set thermal flow, and Newton’s low of heat exchange. That was so 1st time me codind for 2 years, so temperature in corners can be zero sometimes. I cinda know how to correct that, but that’s gonna be next time me doing this stuff