dutycycle:1/3;
square(x) := (if (x-floor(x) > dutycycle) then 0 else 1);
load(draw);
draw2d(terminal=svg,file_name="Dutycycle",
  color=black,font="Times",font_size=15,nticks=75,proportional_axes=none,
  user_preamble="set termoption enhanced;",dimensions=[800,280],
  xtics_axis=false,ytics_axis=false,grid=true,points_joined=true,
  yrange=[-.1,1.1],xtics={["0",0],["tau",dutycycle],["T",1],["T+tau",1+dutycycle],
  ["2T",2],["2T+tau",2+dutycycle],["3T",3],["3T+tau",3+dutycycle]},ytics=1,
  xaxis=false,yaxis=true,axis_top=true,axis_bottom=true,axis_left=true,axis_right=true,
  line_width=2,/*label(["x",1.,0.1],["y",0.1,1.]),*/xlabel="Time",ylabel="Amplitude",
  color=blue,key="",explicit(square(x),x,0,3.5)
);