You can draw an oval given center after finishing the project. Now animate the rotating oval at the fixed center. Also add changing color for fun with colorsys library.
Moving averages can smooth out the stock prices and reduce the randomness. Based on the previous projects (stock price random walk with candlestick chart, and trending stock price random walk
Create 100 turtles with random colors. They all start from position (0,0) and start doing random walk. Also draw the bounding circle with the color of the farthest turtle. Video