* Overlay on a categorical axis
sysuse auto, clear

graph bar price, over(rep78)
graph dot price, over(rep78)
graph box price, over(rep78)

graph box price, over(foreign) over(rep78)

generate price0=price if foreign==0
label variable price0 "Domestic"
generate price1=price if foreign==1
label variable price1 "Foreign"

graph box price0 price1, over(rep78)
drop price0 price1

levelsof rep78, local(rl)
foreach val of local rl {
	generate price`val' = price if rep78==`val'
	local varlbl : label(rep78) `val'
	label variable price`val' "`varlbl'"
}
graph box price?, over(foreign)
drop price?

* see the "separate" command