= #JxnPortable\docs\plot_examples\demos\PerspectiveDemo.jxn

#JXN:include/P3dInclude
i = slider.add( "i", 215, 0, 500 )
!
z = t
x = sqrt t * cos 10 PI t
y = sqrt t * sin 10 PI t
!
ti = i / 500
zi = ti
xi = sqrt ti * cos 10 PI ti
yi = sqrt ti * sin 10 PI ti
vi = @JxnVectorAlgebra( xi, yi, zi )
!
pf = plot( p3d ).add( x, y, z, R ).add( vi, B ).apnd( @JxnVectorAlgebra(0,0,1)-vi, G ).box( vi, @JxnVectorAlgebra(0,0,1)-vi )