Teach your baby math

https://github.com/phma/mirasol
This is my first-started Qt5 program. It shows numbers from 0 to 1000 in any of several shapes (which are available depends on the number, e.g. 91 is composite, centered hexagonal, and triangular). It's inspired by Doman's flash cards, but goes beyond number sense to teach kinds of numbers, such as square numbers. Here's a screenshot showing 144 as a Fibonacci number:
Attachment 12651
The program still has debugging code in it, and I'm not sure what features I should add before releasing version 0.1.0. What do you think?

Aside from code issues, I am truly puzzled as to how the screenshot you posted represents 144 as a Fibonacci number. I didn't count them all, but I assume there are 144 dots in the image, but they appear to more or less randomly arranged in a right triangle. What is the relationship of that figure to a Fibonacci number?

As for code, you should release only programs built in "Release" mode with no debugging message boxes or other outputs that would do nothing except confuse users.

Drop a perpendicular from the right angle to the hypotenuse. The upper part has 55 dots, the right part 89. Each of the two parts can be similarly split, giving 21+34 and 34+55. If you hit the up or down arrow while it's showing a number in Fibonacci shape, it'll show the next Fibonacci number up or down, except:
*from 0, the down arrow does nothing;
*from 1, the down arrow changes it to 0 and the up arrow to 2, even though 1 is twice in a row in the sequence;
*from 987, the up arrow does nothing (the largest number it shows is 1000).