``` PRINT CHR$ 8; OVER 1; "/" ``` Why do you recover an unblemished B? 2. Type: ``` PAPER 0: INK 0 ``` Isn't it just as well that these don't affect the lower part of the screen?\ Now type: ``` BORDER 0 ``` and see how well the computer looks after you!\ But what will happen if you do the same after giving: ``` LAYER 1,3 ``` 3. Run this program: ``` 10 POKE 22527+RND*704, RND*127 20 GO TO 10 ``` Never mind how this works; it is changing the colours of squares on the screen and the **RND**s should ensure that this happens randomly. The diagonal stripes that you eventually see are a manifestation of the hidden pattern in **RND** – the pattern that makes it *pseudorandom* instead of truly random. 4. Type in the chess piece characters in *Chapter 13* and then type in this program which draws a diagram of chess positions using them: ``` 5 REM draw blank board 10 bb,bw=1,2: REM red and blue for board 15 PAPER bw: INK bb: CLS 20 PLOT 79,128: REM border 30 DRAW 65,0: DRAW 0,-65 40 DRAW -65,0: DRAW 0,65 50 PAPER bb 60 REM board 70 FOR n=0 TO 3: FOR m=0 TO 3 80 PRINT AT 6+2*n, 11+2*m;" " 90 PRINT AT 7+2*n, 10+2*m;" " 100 NEXT m: NEXT n 110 PAPER 8 120 pw,pb=6,5: REM colours of white and black pieces 200 DIM b$(8,8): REM positions of pieces 205 REM set up initial positions 210 b$(1)="rnbqkbnr" 220 b$(2)="pppppppp" 230 b$(7)="PPPPPPPP" ```