Adjust the a and b values (lower and upper bound), and n (number of rectangles). Fullscreen mode is recommended.
Riemann Sums: https://en.wikipedia.org/wiki/Riemann_sum Graph Used: https://www.desmos.com/calculator/hjs0stodhp The visual might not be 100% accurate and may seem jumpy/offset. This is because of limitations with the Pen in Scratch.