Much obliged for your help. Logo has the advantage of being immediately applicable to much younger learners (~7) than BJC (~16). There's a big mass of teaching resources (microworlds, etc) that are immediately usable at the beginning, with the possibility of progressing into more complex concepts (e.g., turtle geometry). Maybe, for small children, it'd be a matter of buckling down to port Logo examples to Snap!'s turtle graphics... I may try that.
