It escapes me now _why_ I emailed him. I certainly had no idea the gravity of who he was (for those also unaware, he is perhaps most famous for creating the Build engine used in games like Duke Nukem 3D). I believe I was under the false assumption at the time that the Build engine was a raycaster (I hadn't played Duke Nukem), and I probably found a personal page of his about the Build engine while trying to solve my problem.

Either way, young me emailed Ken Silverman like it was nothing. He responded! He corrected me about the Build engine, but also proceeded to help describe how to render floors in a raycasting engine.

It still took me awhile more to get the hang of the math, and I believe a few more emails back and forth with him. I feel bad now, knowing now who he was. But I appreciated his help immensely. I think I wrote 3 or 4 more ray casting and tracing engines back then. Some were rudimentary, one was a raycaster but allowed arbitrary 2D level geometry (and even used some tricks to put "holes" in walls to cheat windows and have multiple heights). One was for a code golf competition. And one was _super_ efficient; the math and levels were set up such that 90% of the logic was just binary math rather then having to do the usual multiplications, divisions, and square roots. They're a lot of fun to make and I learned a lot.

Ken, if you ever stumble on this comment, thank you!