Place n evenly spaced points on a circle and connect them by skipping k points each time. Depending on the greatest common divisor (GCD) of n and k, you may get one continuous star or several overlapping shapes.
This shape is called a star polygon {n/k}. The pentagram (⭐, {5/2}) is the most famous example.
If gcd(n, k) = 1, you pass through all n points without lifting the pen and draw one continuous star. But if gcd(n, k) > 1, the line returns to its starting point early, splitting into several smaller shapes shown in different colors.