In looking for REPL (it's in the Cuis base as Transcripter > readEvalPrint) I found a new way to get a hang-up. In a workspace do:

(Transcripter newInFrame: (0@0 extent: 100@200))
    nextPutAll: 'Hello there'; endEntry;
    newLine; print: 355.0/113; endEntry;
    readEvalPrint.

...and the clock stops. 'top' reports 100 %CPU for squeak.