Question is in the title :D
You're welcome to interpret black and white as colors or not include them in your color count! We won't crack down on what "qualifies" for the Technical Theme; the goal is to try new things, work with new people, and finish something, so if working with a limited palette grows into something completely different, we welcome that :)
I was thinking that something like this comes as answer :D I will try to count black and white as colors, to get a bigger challenge. But I'm not sure if I will have the energy to participate, because I'm now working for the Butterscotch ShenaniJam 2019 this weekend and next week I have a lot of work to do. Maybe I'm able to make a very tiny game :D