During my apprenticeship as a software developer (~2000ish) I got together with other people from school and we set out to program a game.
I was in charge of doing the 3D engine and here are the results of the first attempt:
First screenshot of the engine 
Single colored quad 
Two colored quads 
First mesh loaded 
Rendered as solid 
Terrain 
Map loader 
Map loaded 
Wireframe of terrain 
Movable camera 
Testing the 3DS loader with a multi-part object 
Testing the 3DS loader with a complex shape 
3DS object with two different materials 
Loading textures 
Textured terrain 
Terrain with blended textures 
3DS object and terrain 
Particles 
More particles 
Particles 
Particles 
Math is fun 
Still! 
Moar particles! 
Fireball! 
Skybox added 
Linear fog added to the scenery 
Fog 
Terrain mesh 
Problems with normals 
Placing objects on the map 
Placing objects 
Object on terrain 
Tower on the map 
Placing objects 
Wireframe rendering of objects 
Fire! 
Fire in pit close-up 
Fire in a pit 
Water added 
Z-ordering works 
Frustum culling test 
Frustum culling a quadtree 
Frustum culling 
Frustum culling 
Sunken trees 
AI test
The terrain was based on a .tga file that looked like this:
Based on the first experiences I wrote a second engine so we could start having more user interaction. That needed some UI components that I’ve mocked-up:
Loading objects with transparencies 
Transparency 
Transparency with moving objects 
Transparent window 
Transparent windows with updating text 
Monochrome with transparency 
Transparent window 
Window ordering 
Statistics
The second iteration looks like it was a step back, but it actually allowed me to prototype things faster. At least it would have, school ended and so did the time to work on this.