This small write-up was originally posted as a Twitter thread about how I drew birds in Mount Doodle. The algorithm is quite simple yet seems to work well. It might give you some ideas if you also consider drawing birds in a landscape scene. 💡

Just like drawing a bird with a pen – each bird consists of 2 strokes, and each stroke is drawn from the body to the tip of a wing.

The fundamental form of strokes is just two lines. Each line originates from the center of a circle and ends at a random point of the circumference.

For each stroke, randomly select a midpoint between the body and the wingtip. Then add some randomness to the position to this mid point. Finally, draw a curve that connects these 3 points (i.e., the body point, the mid point, and the wingtip).

Draw the curves with bolder stroke weight – these already look like birds IMHO. 😆

To make it look more organic, add some randomness to the positions of the body point and the midpoint to create another pair of points: body' and mid'. Then connect the points with a curve: body, mid, wingtip, wingtip, mid', body'.

Fill the shape with colors. Hmm, it looks a bit weird when the curve twists in the middle. 😅

A quick fix – draw thick outlines! Now the odd twists are barely noticeable. 🤣

Finally, paint both strokes with the same color. And we’re done. 🥳