On Wed, Jul 27, 2011 at 12:33 AM, Juan Jose Garcia-Ripoll <juanjose.garciaripoll at googlemail.com> wrote: > XCode 4 is no longer free, am I wrong? William Stein has a public-facing box sqrt5.cs.washington.edu (which used to be bsd.math.washington.edu) with 10.7 and XCode4 installed on it. You may already have an account there. --Mike