I also like that music visualization :-) Even though it’s not how I visualize sound when I compose.

But I don’t understand something. Were you claiming that 1+2+3+4+…+100 = 100 x 100 ?!

Mathematicians as a group have not frequently been accused of proficiency in arithmetic.

How about the trick for visualizing this attributed to 7(?) year old Gauss. Add from the outsides. 1+100 = 101. 2+99 = 101. 3+98 = 101. Etc. So 1+2+3+4+…+100 = 101*100/2 = 5050.