Here are the external resources I used for my coding projects. I try to credit everything that's not by me.
Scale puzzle background: https://www.freepik.com/premium-vector/seamless-texture-printing-fabric-paper-dancing-skeletons_30382661.htm by nishman
Scale puzzle border: https://www.freepik.com/free-vector/halloween-border-hand-drawn-collection_9938401.htm
Confetti gif: https://gifer.com/en/6SSp by Madred
Music: Coconut Land by Filippo Game Audio
Explanation page background: More Leaves On Green Pattern by Tomislava Babić, https://www.toptal.com/designers/subtlepatterns/more-leaves-on-green-pattern/
This uses the following works by M. C. Escher:
Stars, 1948 (this one depicts chameleons)
Tetrahedral Planetoid, 1954
Double Planetoid, 1949
Sphere Surface with Fishes, 1958
Concentric Rinds, 1953
Sphere Spirals, 1958
The background is Glitter stars by MalyskaStudio: https://www.freepik.com/premium-vector/glitter-stars-decorative-vector-seamless-pattern-repeating-background-tileable-wallpaper-print_36179603.htm
Ocean gif is by @headlikeanorange, https://giphy.com/gifs/headlikeanorange-ocean-sea-headlikeanorange-WLmGdJBTGz7Lq
The lemons are traced and vectorized from https://pngtree.com/freebackground/cute-lemon-leaves-repeating-tile-pattern-background_1173351.html by houbor
By the way, that description is a lie, this is not a repeating tile. But the lemons are actually cute, at least.
Stone texture: https://www.cadnav.com/textures/7834.html
I edited the papyrus texture into a repeating tile from this: https://www.freepik.com/premium-photo/old-papyrus-background-texture_44287794.htm by daboost
The papyrus plant borders are traced and vectorized from this papyrus: Analysis of the pigments in two modern Egyptian papyri using XRF technique - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Papyrus-2-The-hunting-scene-of-the-Tomb-of-Nakht_fig2_354821585
Costa Nardes, Raysa & Sanches, Francis Anna & Filho, Hamilton & Freitas, Renato & Assis, Joaquim & Anjos, Marcelino. (2020). Analysis of the pigments in two modern Egyptian papyri using XRF technique. Brazilian Journal of Radiation Sciences. 9. 01-16. 10.15392/bjrs.v9i1A.1459.