(- impl fix) Properly *call* inspect!
(new infra) Implement the first few Thing API aliens
(new infra) Implement most of the remaining Thing API
(- re style) Consistently indent entries
(- fix infra) Call the appropriate clone regardless of type
(new infra) Implement Label's API
(- doc new) Note error-handling situation
(new infra incomplete) Implement several Execution procedures
(- new impl) Exposing `void`, probably temporarily
(- fix infra) Make `stage`'s result explicit