Reflection
I have been familiar with optical illusions in breadth, mechanics, and execution, so while it may be easy to design something involving optical illusions, making something ingenuous I have not previously considered or seen is challenging.
Well, how about this? All of the examples of parallel projection paradoxes presented seem to be orthogonal in nature. I think that breaking this restriction and would contribute an additional level of trickery. This is challenging, of course, because as evidenced, humans tend to follow lines along orthogonal planes, and decomposing perpendicular lines may cause a loss of illusion, depending on how the image is structured. Alternatively, it might contribute to the illusion further, given how it is harder to follow. Should I exploit this illusion, though, I will really have to be mathematically meticulous and plan my work ahead.
Additional Sources
Aronsson, Andrea. "Gallery." A. Aronssons WeBOLLog. 29 Oct. 2010. Web. 15 Oct. 2015. <http://andreasaronsson.com/impossible-figures/gallery/>.
Blankenbehler, Benjamin. "How Greek Temples Correct Visual Distortion." How Greek Temples Correct Visual Distortion. 14 Jan. 2014. Web. 15 Oct. 2015.
Westerdiep, Arjan. "Drububu's Pixel Art Tutorial." Drububu.com. Web. 15 Oct. 2015.