Levels 1-10
Blek Guide
This section of the guide aims to provide the information that you need to beat every level in Blek.
Level 1
Simply draw a straight, horizontal line.
Level 2
Starting in the middle, draw a flat line from left to right. It will hit the right-hand wall and bounce back to the left, hitting the second circle.
Level 3
Draw a straight, diagonal line, from the bottom left to the top right.
Level 4
This is the first level where you have to avoid a black circle. To do so, draw a curved, wavy line that goes up and down, ending at the bottom of the first blue circle. It will repeat itself, hopefully avoiding the black circle, before hitting the second colored one.

Level 5
For this, you just need to hit all of the four circles that are laid out in a square. You can do it in a number of ways - drawing a quick, large, jagged or curved line that repeats itself with each jagged or curved bit very close together so that it covers all of the circles. You can also draw squares like on a castle's battlements to do the same job.
Level 6
For this triangle of circles, use any repeating line to avoid the black.
Level 7
For this one, pretend you are drawing stairs that start at the bottom left, ending at the bottom of the first red. They will repeat, hopefully hitting the colored circles and missing the black one.
Level 8
Draw a zigzag, starting above the left-most black circle, then dipping underneath the next one, before coming up again just underneath the first blue circle. It should repeat and hit the others.
Level 9
Draw a square with the same orientation as the circles, but below them, starting with the top edge and working anti-clockwise. With the final edge (which should be the one on the right), extend it so that the square is repeated where the colored circles are.
Level 10
This level introduces using 'turret' circles to fire at other colored circles encased in black. Luckily the turret isn't spinning, though they usually are. Simply draw a line from the right-hand side of the screen towards the turret, but it needs to be at enough of an angle that your line won't carry on and hit the black.