Drawing Graphics (BBC Micro)

3min
A great demonstration of the power of the BBC Micro, and the start of thinking about game code is to write a really simply program that draws random lines from the center of the screen outwards.
The really short code is below.
Line Drawing
Briefly to explain it, we set the screen to high resolution mode (1000x1000px) using MODE 0 command. After this we generate 2 random numbers stored in variables X and Y. Finally, we move the cursor to the center (500,500) and draw out to wherever the random numbers tell it to.
VisualBasic
10 MODE 0
20 X=RND(1000)
30 Y=RND(1000)
40 MOVE 500,500
50 DRAW X,Y
60 GOTO 20
10 MODE 0
20 X=RND(1000)
30 Y=RND(1000)
40 MOVE 500,500
50 DRAW X,Y
60 GOTO 20
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Colors
With a small tweak we can go to a color mode (mode 5), and generate a random color.
The BBC can only do 4 colors. Black, red,yellow and white. So we generate a random number between 0 and 3.
Note that GCOL0 is a zero not the letter O.
Also, we removed the MOVE command so it simply draws from 
VisualBasic
10 MODE 5
20 X=RND(1000)
30 Y=RND(1000)
40 C=RND(3)
50 MOVE 500,500
60 GCOL0,C
70 DRAW X,Y
80 GOTO 20
RUN
10 MODE 5
20 X=RND(1000)
30 Y=RND(1000)
40 C=RND(3)
50 MOVE 500,500
60 GCOL0,C
70 DRAW X,Y
80 GOTO 20
RUN
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Boot Up Diagnostics (BBC Micro)
Loading from Floppy (BBC Micro)