import graph; unitsize(1cm); xaxis("$x_1$", xmin=-3,xmax=2, Arrow); xaxis(axis=YEquals(-2), Label("$x_2$",align=N), xmin=-1,xmax=3,blue, Ticks(), Arrow); xaxis(axis=YEquals(-4), Label("$x_3$", align=N), xmin=-3,xmax=2,red, RightTicks(NoZero), Arrow); xaxis(axis=YEquals(-6), Label("$x_4$", align=NE), xmin=-1,xmax=3,blue, RightTicks(Step=3,step=.5,end=false), Arrow); xaxis(axis=YEquals(-8), Label("$x_5$", align=NE), xmin=-3,xmax=2,red, RightTicks(Step=2,step=.25,end=false), Arrow); shipout(bbox(3mm,Fill(white)));