Since 2013, i tried a lot of approaches in tiny intros for MSDOS, with the exception of : 3D raycasting. As a computer scientist with specialisation "computer graphics" i simply was not interested enough in manually asm-coding a brute force raycaster, with regard to already existing, excellent examples like "Spongy" (128b, TBC, 2009) and "Wolf128" (128b, Baudsurfer, 2014). However, i coded several "2,5D" effects like "Lucy" (64b, 2014) and recently "Projektbeschreibung" (32b, DESIRE, 2018). So naturally, at some point i asked myself, what is the smallest 3D raycaster which is perceived as one, being centered, having decent textures and colors, and runs on all common systems (MSDOS, FreeDos, WinXP Dos, Dosbox) while being totally smooth at least on real hardware? The (my) answer is :
 
49 bytes
 
That "pure" version is included in the archive - as well as a *43* bytes version which lacks all the criteria above. Going lower in size means that you abandon the "3D" and "raycasting" at some point, leading to something like "Floorcast" (32b, DESiRE, 2018)