from pylab import *
X,Y = meshgrid( arange(0,2*pi,.2),arange(0,2*pi,.2) )
U = cos(X)
V = sin(Y)
quiver( X, Y, U, V, 0.2, color=True )
show()
quiver( U, V, 0.3 )
show()
quiver( U, V, color=True )
show()
quiver( U, V, color=U+V )
show()
quiver( X, Y, U, V )
show()