Reading through the challenges, the last one seemed like a big leap. Made me think of the “learn to draw” meme that progresses quickly from simple shapes to a simple cartoon and a god leap to a super realistically rendered pencil drawing.
It might seem complicated at a glance, but if you look through the implementation guidelines / rules / description, it's not that big of a leap. It has clear requirements and the paper[1] outlines everything together with example code (in both JavaFX and ScalaFX), and it's not a "god leap" if you have at least a bit of experience building UIs.
- [1] "Comparison of Object-Oriented and Functional Programming for GUI Development" - Eugen Kiss - Page 49 - 3.9 Cells
Neither is it really a "god leap" in the art analogue either, that's what makes it a particularly apt analogy, I think. The implication in the art example is "iterate the above techniques a large number of times to obtain a finished result like this". It seems like a "god leap" because most people don't see the thousands/millions of iterated steps, they see the finished product as a finished product without the intuition of the component parts. That does seem to apply to the Cells project here: most of the same underlying components but yes iterated far enough and long enough it seems like a more insurmountable leap than it should without the right intuition pump.
Well, not a lot seem to have bothered. There are JS spreadsheet implementations in 200 lines, so it's not that it's very difficult, more like this didn't have enough exposure to attract programmers yet -- for example there's not a Cocoa or SwiftUI implementation.
https://eugenkiss.github.io/7guis/implementations