don't recompute the thing on which you iterate
don't recompute the thing on which you iterate

mockingbirdnest/Principia,pleroy/Principia,pleroy/Principia,mockingbirdnest/Principia,pleroy/Principia,eggrobin/Principia,eggrobin/Principia,pleroy/Principia,mockingbirdnest/Principia,eggrobin/Principia,mockingbirdnest/Principia