Each of the players at {TAIL ~ his turn} can, if he elects to contribute to a word, generate a number of chance from {HEAD ~ a selected set} of numbers 
Each of the players at { TAIL ~ his turn } can , if he elects to contribute to a word , generate a number of chance from { HEAD ~ a selected set } of numbers
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH