Fast and tricky, M. Percy's Maggots will soon have you wriggling at the keyboard

This addictive high-resolution game for the Dragon 32 does wonders for the reflexes and gets away from the era of laborious games with a ready-set maze.

Due to the amazing speed with which the Dragon works in Basic, this game - in which a red maggot runs around the screen and searches for food - can by very hard. A speed option is offered: this is done by setting the internal timer to a running speed of 1.8 MHz instead of the default of 0.9 MHz.

The idea is to move the maggot - which starts off in a random direction, but always from the centre position - round the screen, to the clumps of food which are represented by green dots. Movement is achieved by the use of the arrow keys. When a clump of food is eaten, the maggot increases by a length or two.

Turning should be kept to a minimum because the maggot sloughs its skin. If the maggot hits this or the border then the game is lost. As more and more corners are turned the screen fills up with red lines. The bigger the maggot the longer the barricade of dead skin will be.

When the maggot has reached a length of 40 units, the game stops for five seconds. The screen then clears and play starts again, but instead of starting off 10 segments long, it starts with two so that more epithelia will be discarded, making the game harder than before. When three sets have been cleared the internal timer is set to Fast mode so that the game, if started in Slow, will now be fast. The game then continues with a new set appearing each time the maggot attains a length of 40 units.

Due to the way the end of the maggot is preset to keep it at the length specified by ML and the variables I and O a skin or skin segment immediately behind the maggot may disappear. This will only happen when turning and may beused to an advantage to reach food which was inaccessible - but be careful that the food is not erased as well.

Lines 20-30 clear room for the strings and set all necessary variables; lines 50-60 determine speed; and lines 70-120 set display.

In line 130, the GOSUB moves to the food routine: the GOTO is for starting the game.

Lines 150-200 place a clump of food in a random position with line 170 checking to see if the point is already set to read, and if so starts the routine again. Up to four blocks of food may appear in one clump or as little as one - variable M determines this. Line 150 places the food in the yellow area of the screen only. Line 230 starts the maggot moving in the appropriate random direction by the variable SM, and goes to the appropriate line number; lines 240-280 send control to the appropriate line number, and line 290 checks to see if any of the arrow keys have been depressed.

If none has been depressed or if the reverse key has been pressed, then the maggot carries on moving in the same direction or else goes back to lines 240-280 for the next direction.

Line 300 checks to see if the next point to be PSet is red and if so moves the losing routine at 580. Line 310 checks to see if the next point is food and if so goes to the appropriate routine.

Lines 330-350 subtract the length of the maggot from the PSet position and preset these points so that the maggot does not appear as one continuous line.

Line 590 speeds the routine up and 700 slows it back donw. Lines 790-850 search for food in an area of three by three around the maggot's head and for each little block found five points are added to the score. Line 840 then presets these points so that no food is left in that area. Line 860 goes to the routine for placing some more food in another random position. Line 870 adds two to the length of the maggot. Line 880 checks to see if it is 40 in length and if so goes to the routine at 900.

Lines 900-950 clear the screen and add 1 to the amount of sets cleared. Line 940 makes the game fast if a fourth set is reached. Line 950 gives the maggot a length of two and continues the game. Variable ML can be changed in line 880 to make the game easier or harder.

This game was originally published in Your Computer Vol. 3 No. 3 (Page 64).