Simple 3D Box
3 Dimension or 3D graphics in Qbasic is nothing , but including an additional 'z' axis and to extend the 2 dimensional structure along that axis. This can be achieved by drawing a box, or the structure you want , each time at a new x and y position. It is quite like animation, except, we do not erase the structure after it being drawn , and there is no need of any intermediate pause. You can better understand by looking at the 3d box program given below.
Redo: cls screen 1 Input "Enter the X-position?";k 'entering coordinates of the screen from where to start. Input "Enter the Y-position?";l ' this also determines the size of the box. color 1 for i = 1 to 50 step 2 rem box ' step to ensure space between the boxes, make it one to eliminate the space. The 50 number sets the extension of the box along the z axis a = k+i:b = l+i ' this "for-next" loop draws the box over and over again, each with incremented values of k and l. line (a,a)-(b,a) line (a,b)-(b,b) line (a,a)-(a,b) line (b,a)-(b,b) next rem diagonals line (k,k)-(a,a) ' the four diagonals to the structure , which make it more realistic line (l,l)-(b,b) line (l,k)-(b,a) line (k,l)-(a,b) Input"Do you want to redo? (Y/N)";ans$ if ucase$(ans$)="Y" then goto Redo end