Slicing watermelon: Use 2B pencil to see the whole watermelon as a triangle. (1) Draw a triangle first, then draw a straight line near the bottom, and draw three points on the straight line;

(2) The lower part of the line is painted green and the upper part is painted red.

Half a watermelon: (1) Draw a semicircle first, then draw an arc on the semicircle, and point several points on the arc;

(2) The arc is painted green below and red above.

A watermelon: (1) Draw an ellipse first, then draw a horizontal wavy line inside the ellipse, and draw a small tail outside the ellipse;

(2) The wider part between wavy lines is painted green, and the narrower part is painted black.