First strive for clearness in the reproduction and ability to keep
the images separate. The reproduction of letters and figures in the
exercises for visualization on page 46 will accomplish this result.
Problems in mental arithmetic, if visualized, are of great value in
that the correct solving of them requires vivid and separate images.
Work for fullness of detail, the picture frame suggested on page
74 offers an excellent opportunity to do this while exercising the
constructive imagination. While fixing the attention upon the square
you keep the element of change going by use of the imagination in
picture making. Put into this picture all the detail possible, add
everything you can think of and then strive to create still more.