Because everything must be contained in a rectangle we must allow for a certain compression. However, no matter how much we are forced to change our original idea or drawing, the vitality and force of that idea will be retained when all the changes take on a unity. To make a picture function, each part must interlock with the other and finally with the canvas rectangle itself.
Actually the unity need not be forced into being. We all have within us the ability to judge when a thing looks right or not. It is one of the greatest strengths we possess.
Unfortunately this valuable instinct is so overladen with prejudice and acquired bad habits of thinking, it becomes swamped and blunted. After you have done a few paintings, however, you will soon overcome that difficulty and very quickly assess your shapes and arrangements spontaneously and correctly.
You will also see the need for the simple placing of unequal rectangles, triangles, simple directions and movements discussed above. These simple shapes are easily unified and so give authenticity and truth to your painting.
However, I don't wish to labor this point too much. The fun in picture making is similar to any form of drawing or painting. With experience you will come to arrange your pictures naturally to suit your subject, breaking or adapting the laws of nature as you feel inclined.
DRAWINGS INTO PICTURES
For hundreds of years, at least from the beginning of the fourteenth century, it has been the practice first to make drawings and then compose these drawings into pictures. The drawings would be made from nature and drawings would then be made from these drawings. Finally, they would be made into paintings. This way all the most awkward problems in making nature fit into a picture were solved. What held then still holds good today.
When you begin you may have an idea, a landscape, say, with figures, and a certain mood is conjured up. You remember the scene well. You think it will make a fine picture. It means something to you. Well then don't start painting it up right away. Think about it first on paper. Make a few drawings.
On the other hand you may have a series of drawings and sketches you did last summer, all fragmentary, but well detailed and documented. You think that you would like to make them into a picture. Your problem will be the same. To sort out the drawings and to put them together into a composition that will fit your canvas.
Again. you may have a drawing that is almost right for painting up but just needs a few alterations here or there. The same principle applies. Make further drawings until those alterations are just right.