Type (1)141:The positions of the four squares in the middle are unchanged. Draw a square above and below them as the upper and lower bottom surfaces, and there are six kinds of * * *.
(2) Type 23 1: the number of squares in the first row to the third row is 2, 3 and 1 respectively, and the middle row has three squares as sides, with three kinds of * * *.
(3) Type 222: The number of squares from the first row to the third row is 2, only 1 species.
(4) Type 33: * * two rows, each row is three squares, and only one square can be connected between the upper and lower rows, only 1 species.
On the basis of the above, it can be folded along the edge of the square to form a cube.
It should be noted that when four squares in a square expansion diagram are connected to form a "field", the expansion diagram cannot form a cube.
Painting skills:
1. Preparation tools before drawing: drawing paper, different types of pencils. Drawing paper needs thick white paper with irregular lines. Friction-resistant, so you can use an eraser when painting, and it is not easy to get fuzzy. And it has good water resistance, so when painting watercolor, there will be no diffusion.
2. Learn to draw lines: Sketch is made up of lines. Before you learn to draw, you have to draw a lot of lines, but you just draw lines.
Don't bend when painting, pay attention to decisiveness, chic and appropriate strength, that is, a line should make people feel beautiful, straight and generous, and the tail should be well gathered and organized. The key lies in the processing of line density, the rhythm coordination and ingenious application of density relationship, which can keep the picture sense of order and produce an orderly, rich and uncomplicated picture.
3, copy sketch photos: after learning the lines, choose a few photos you like to copy. Copying is the process of copying calligraphy and painting according to the original. For beginners, copying and sketching are also important. But beautiful scenery, scenery, food, as long as you like. Just copy a sketch photo and draw the outline.