Problem
Write a function that inputs a frequency, a maximum amplitude, a percentage of blend (e.g., 0.25 to represent 25%), and length in seconds. Create two sounds, one a square and one a triangle, using the same inputs. Add the sounds together, with the blend percentage of the square and 100-blend of the triangle. How does the sound change if you try 0.25, 0.5, and 0.75 as the blend percentages?