The LensLok is a device which was used on several titles to prevent pirating. The device resembles a small plastic card with two folding edges and a plexi-glass lens / window in the centre. The general idea was that when the game or application had loaded, a scrambled code would be displayed on the screen, which could only be decyphered using the lens. The system was extremely difficult to use on the original CPC monitors and trying to use it on a TV / MP1 / 2 setup was totally pointless.
The following software used the LensLok system as a protection method: (Possibly not complete, please add more if you know of any)
The following instructions are based on the original description supplied with the game Tomahawk, other titles may have used other methods or steps.
1. After the game has loaded a wide 'H' shape is displayed in the centre of the screen. The unfolded LensLok is held up to the screen horizontally aligned with the cross-bar of the 'H'. Using the keyboard, the user adjusts the size of the 'H' to match the dimensions of the LensLok.
2. After the screen has been calibrated, a scrambled 'OK' is displayed on the screen. To read this, the LensLok is folded at both ends, turned 90 degrees and aligned with a vertical line in the centre of the scrambled symbols. When the user has recognised the 'OK', by closing one eye and viewing the code through the prisms of the LensLok, they can advance to the actual code.
3. Using the method described in step 2 (or just not moving either your hand or eye position) a two letter code is now shown on the screen. The user must enter this code to continue to the game.
A few notes from a user whose favourite game (Tomahawk) was ruined by the ordeal of having to go through this ridiculous ritual every time I wanted to play the game. Firstly, if you were one of those lucky children who were greeted by a 6128 under the Christmas tree sometime in the mid 80's then I'm very happy for you, I wasn't one of those. So loading Tomahawk already meant sitting for 58 minutes in front of the CPC waiting for it to load (the first few attempts at loading the game usually ended in a load error 20 seconds before it was completed!!!), after that, it was a 20 minute battle with a fiddly piece of plastic, trying to recognise two stupid letters. If I wanted to play the game on a TV, I had to carry my GT64 into the living room too, because the LensLok was impossible on a jittering modulated TV screen. Many failed attempts and asking my brother to 'have a go' at recognising the letters usually ended in total frustration and I ended up playing Jet-Set-Willy instead. This was a terrible invention which never should have happened. I hope the inventor of this device, whose only goal was to torment small children, ended up working in the sewers...
Ok, I've calmed down again now. Below are some pictures of this wonderful device and the original instructions from Tomahawk.