The 2-3-4 right triangle. What's the problem?
The intent was apparently to use nuts to represent edges, but he put them on points instead.
The artist's realization isn't even correct.
3-4-5 describes the length of each side - if you count the lengths of the triangle drawn in the image (the lines of chalk visible between the nuts on each side), it's only 2-3-4. To get 3-4-5 you're counting the number of nuts on each side, but those aren't lengths - those are the number of points marking the start/end of each unit length.
I thought there was some point being made about the use of nuts vs. some other arbitrary item. Why does it matter they are hazelnuts and not something else?
X--X--X
0 1 2
X--X--X--X
0 1 2 3
(A 2-3-4 triangle is not a right triangle, no angle is 90º)
"The artwork references the idea of relating the lengths of the sides of a 3-4-5 right triangle ..."
How on earth did you get 2-3-4 for a right angled triangle! I blame booze, drugs, a late night or perhaps a standard issue: "off by one" (this is HN after all) ...