# Tweet by [@keefmoon](http://twitter.com/keefmoon) on 2016-08-02 19:09:30 > [!INFO] Archived from [original tweet](http://twitter.com/keefmoon/status/760553126369890304) RT @borkware: Swift existential containers have three*sizeof(pointer) fixed-sized buffer. Why three? (vs say 4 that could hold a CGRect)