#lang scheme
(require plot)

(define (trig x y) (* (sin x) (sin y)))

(plot (mix (shade trig)
           (contour trig)
           (vector-field (gradient trig) #:samples 25))
      #:x-min -1.5 #:x-max 1.5 #:y-min -1.5 #:y-max 1.5
      #:title "gradient field +shdade + contours of F(x,y) = sin(x) * sin(y)")

(plot3d (mesh3d trig)
        #:x-min -3.5 #:x-max 3.5 #:y-min -3.5 #:y-max 3.5 #:z-min -1.0 #:z-max 1.5
        #:bgcolor '(0 0 0) #:fgcolor '(255 0 0))