# Author: Ika, 9/1/2013. # Code to generate the last frame.  from matplotlib.pyplot import * from numpy import linspace, arange from matplotlib.patches import Polygon   x1 = linspace(0,9,100) y1 = 3100/x1 x2 = linspace(1,8,8) y2 = 3100/x2 x3 = arange(1,6,0.01) y3 = 3100/x3 verts = [(1,0)] + zip(x3,y3) + [(6,0)] poly = Polygon(verts, facecolor='yellow',edgecolor='k')   fig = figure(figsize=(5,5)) ax = fig.add_subplot(111) ax.grid(False) ax.plot(x1,y1) #ax.plot(x2,y2,'ro') ax.add_patch(poly) ax.text(4,2500,r"$PV=RT=3100 J$",size=20) ax.text(1.1,3100,"1",size=36) ax.text(6,530,"2",size=36) ax.text(1.2,400,r"$W=\int_1^2P\mathrm{d}V$",size=20)   ax.set_ylim(0,3720) ax.set_yticks(linspace(0,3100,6)) ax.minorticks_on() ax.set_xlabel("V") ax.set_ylabel("P")   fig.savefig("isothermal_5.png",bbox_inches="tight",\         pad_inches=.15)