Spiral

Spiral.java

public class Spiral {
    
    public static void main(String[] args) {
        Drawing d = new Drawing();
        spiral(d, 4);
    }
    
    static void spiral(Drawing d, int n) {
        // Base case
        if (n > 0) {
            // Make input smaller
            spiral(d, n-1);
            
            // Combine smaller step with current step
            d.drawLine(100 + -20*n+20, 100 + -20*n, 100 + 20*n, 100 + -20*n);
            d.drawLine(100 + 20*n, 100 + -20*n, 100 + 20*n, 100 + 20*n);
            d.drawLine(100 + 20*n, 100 + 20*n, 100 + -20*n, 100 + 20*n);
            d.drawLine(100 + -20*n, 100 + 20*n, 100 + -20*n, 100 + -20*n-20);
        }
        else {
            d.drawLine(100, 100, 100, 80);
        }
    }
}