Скачать или смотреть BASIC Graphics on FreeDOS

After buying a thin client for £13 as a DOS machine, I installed FreeDOS and a BASIC interpreter to do some graphics experiments. I'm new to this flavour of BASIC (I think it is QBASIC, it doesn't actually say anywhere) and to DOS in general. I set myself the challenge of doing 3D graphics from scratch without looking up how to do it (I've mostly used the built in help for command Syntax and a small amount of online search to find commands I wanted). I also made a simple "Spirograph" type program which allows you to enter the annulus diameter, planetary diameter and pen radius on a basic simulated Spirograph.

It's nice to be programming in BASIC as it is the first programming language I learnt as a child, although I started with BBC BASIC on my first computer, an already elderly BBC Micro.

For anyone giving it a go, it's all school maths, nothing past G.C.S.E. Break the problem down and work out each part on its own on bit of paper, then combine them. The worst bit is defining the models, which I did by hand on graph paper. Initially the cube model was hard coded in the listing, but I realised it was easier to read in more complex models from an external file as CSV.

One pitfall is that to rotate objects I used Inverse Tan, but you need to check what quadrant you're in and add pi if you're in the... second or third quadrant? Basically if Y is negative, add pi to the resultant theta. ;)

There are absolutely better and faster ways to do everything I did. I'm not a programmer, mathematician or even competent.