"---common sphere description with three arguments---"
VARS 1 TRIADIC
	"space centre radius"
	@.r1 SET
	SWAP INTERVAL SWAP SUBTRACT
	"The sphere:"
	MAGNITUDE .r1 NOTGREATER
	"The printout:"
	'*' MULTIPLY;
OPERATOR @sphere SET.

'<space> <centre> <radius> sphere' PRINT.

"---stack efficient call---"
TRIADIC
	"radius centre space"
	SPACE CENTRE MAGNITUDE NOTLESS
	"The printout:"
	'*' MULTIPLY;
OPERATOR @SPHERE SET.

'<radius> <centre> <space> SPHERE' PRINT.


"---automatic centre calculation, (CHECK!)---"

VARS 1 MONADIC
	"space - a 1-dimensional to 8 dimensional number"
	DUP 2 DIVIDE DUP MAGNITUDE 0.6 MULTIPLY @&1 SET SWAP INTERVAL SWAP SUBTRACT
	"The sphere:"
	MAGNITUDE &1 NOTGREATER
	"The printout:"
	'*' MULTIPLY;
OPERATOR @spher SET.

"'<space> spher - automatic centre/radius calculation' PRINT."