A base 10 of {HEAD ~ the work platform} is supported with a bracket 9 at, {TAIL ~ at least, three supporting portions} 
A base 10 of { HEAD ~ the work platform } is supported with a bracket 9 at , { TAIL ~ at least , three supporting portions }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL