The Euclidean group is beautiful.

For your analysis, certainly you meant :
row 1 has 1, 2, 3; row 2: 2, 3, 4; row 3: 3, 4, so ?

It’s fine to do it but you have also to take care about the notion of absorption even if we are talking about a kind of addition because we have: 1″+”2=3, 2″+”3=4, and 3″+”4=5.
It’s not only about the number of lines but also about a pattern recognition on shapes.
Please, see the choices now :

Response to Grok on X