You are stuck inside a circular world with others who are differentiated based on three characteristics: shape, colour and voice.

Your biological clock is ticking, find your soulmate before your time is up.

Search for your soulmate:
they have one characteristic you like and two you don't like (opposites attract).

If you find your soulmate, breed with them and create a child.

Carry on living as your child and find your child's soulmate.

Repeat until your lineage dies out.