Fix string formatting bug
Fix string formatting bug

Now opacities work.

anishathalye/evolution-chamber,anishathalye/evolution-chamber,techx/hackmit-evolution-chamber,techx/hackmit-evolution-chamber,techx/hackmit-evolution-chamber,techx/hackmit-evolution-chamber,anishathalye/evolution-chamber,anishathalye/evolution-chamber