Just a try.
I searched for free picture around the words lighthouse and/or (mosaic patchwork painter���).
A bit like this one (which is not free).
Also, I kind of like the spiral effect which evoke practicing the internal��� and the spiral effet (learning/getting better).
There are some other free and available. This one is Creative Commons:
=> google image searches on �� free �� internal stairs.
I also searched for �� lighthouse anatomy / internals ��. It���s nice but don���t think usable out of the box. It should be stylized (and eventually adapted to programming internals).
https://commons.wikimedia.org/wiki/File:Antique_-_Maniguin_Lighthouse_-_Original_Spanish_design.png. Section_of_new_Eddystone_Lighthouse.jpg.
C��drick (preference for the spiral effect)