Koch Island: António Miguel de Campos | https://en.wikipedia.org/wiki/Koch_snowflake#/media/File:Von_Koch_curve.gif
Hilbert Curve: Vahram Mekhitarian | https://commons.wikimedia.org/wiki/File:Recuesive_Curve_Hilbert_H_Animated.gif
Cylinder: PGFPlots | http://pgfplots.net/tikz/examples/cylinder-spiral/
Mobius Strip: PGFPlots | http://pgfplots.net/tikz/examples/moebius-strip/
Intersection Surfaces: PGFPlots | http://pgfplots.net/tikz/examples/intersection-surfaces/
Fractal Surface: Samuelswatson | https://commons.wikimedia.org/wiki/File:Discrete_Gaussian_free_field_on_60_x_60_square_grid.png
Folder paper cones: https://www.templatemaker.nl/en/cone/
Sphere: Public Domain | https://www.publicdomainpictures.net/en/view-image.php?image=170721&picture=grey-sphere
Saddle surface: Favpng | https://favpng.com/png_view/slopes-saddle-point-maxima-and-minima-graph-of-a-function-png/CPCR3W6g
Stiff paper, Folded Paper: Krishnanand J | https://physics.stackexchange.com/questions/473061/why-do-we-bend-a-book-to-keep-it-straight/473105
Leaf: Shutterstock royalty free | https://www.shutterstock.com/
Pringles: Aatish Bhatia | https://www.wired.com/2014/09/curvature-and-strength-empzeal/
Pringles shaped saddle: Aatish Bhatia | https://www.wired.com/2014/09/curvature-and-strength-empzeal/
Reactor chimneys: User:zootalures | https://commons.wikimedia.org/wiki/File:Didcot_power_station_cooling_tower_zootalures.jpg
Curved space time: http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/grel.html
Red blood cells: Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. | https://en.wikipedia.org/wiki/File:Blausen_0761_RedBloodCells.png
Cell membrane: Lázaro, G. R., Pagonabarraga, I., & Hernández-Machado, A. (2015). Phase-field theories for mathematical modeling of biological membranes. Chemistry and physics of lipids, 185, 46-60.
Coronavirus: https://www.npr.org/sections/goatsandsoda/2020/01/22/798277557/how-does-wuhan-coronavirus-compare-to-mers-sars-and-the-common-cold