// Anything with two slashes before it is ignored by the program and as long as I don't hit return, the line autowraps round, with a little symbol automatically appearing at the right hand side of the line.

// draw rectangle 50mm long, 30mm wide, yellow by default

square([50, 30]);

// Now draw a square 20mm by 40mm, shifted by 60mm in the x direction and 10mm in the y direction - again default colour yellow

translate([60, 10]) square([20, 40]);

// Now similar, but colored (US spelling) cornflower blue (!)...colours are on this page: https://en.wikipedia.org/wiki/Web_colors

color ("CornflowerBlue") translate([-60, 10]) square([20, 40]);

// Or at an angle of 30 degrees (anti-clockwise)

color ("Maroon") translate([-60, -40]) rotate ([0,0,30]) square([20, 40]);

// Now draw a circle

color("Purple") translate([-20,-20]) circle(r=15);

//Now a polygon, which is a section of a castle...laid out a little differently to hopefully make it as clear as possible what is going on (note: refers to Rich's dimensions drawing first)...

// first all the x, y coordinates for all the points, stored as points p1 to p12

p1 = [0,0];//bottom left corner
p2 = [125,0];//bottom right corner
p3 = [125,50];//top right corner
p4 = [100,50];
p5 = [100,37.5];
p6 = [75,37.5];
p7 = [75,50];
p8 = [50,50];
p9 = [50,37.5];
p10= [25,37.5];
p11= [25,50];
p12= [0,50];

list_of_points_P = [p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12];

color("green") translate([0,-55]) polygon(list_of_points_P);

// If we wish to 'subtract' a window sized opening from our castle, we can use the difference command to do the subtraction...

// first list the points for the window opening, as w1 to w4

w1=[37.5, 20];
w2=[87.5, 20];
w3=[87.5, 28];
w4=[37.5, 28];

list_of_points_W = [w1,w2,w3,w4];

color("Red") translate([0,-110]) difference(){polygon(list_of_points_P); polygon(list_of_points_W);}

// for more commands, with links on how to use them, see the following link, though note that this package does 3D as well as 2D drawing... http://www.openscad.org/cheatsheet/

// When you're ready to create a DXF for laser cutting, press F6 first (or select Render under the "View" ment, then when it has finished rendering, go to File>Export>Export as DXF