@LordDeathera (View Post)
There are different types of lasers you can make, but not all of them work the same, I will only explain one of them.

So the most common lasers are probably the ones that use photons (PHOT found in the radioactive category), photons travel in straight lines, they are hot and can be easily customised, so they are great for lasers. There is an element in the special category called clone (CLNE), when you place a dot of that element and then make it touch anything, it will clone that thing, so you can use it to clone photons. Because photons can be emitted from 8 different directions and we only need to shoot in one direction, we need to block the other 7 locations using an element that isn't effected by heat like diamond (DMND from the special category).
GIF: http://imgur.com/ahO5Pix.gif
Fixed GIF: http://imgur.com/t10idVt.gif

There are two problems with this design, there isn't a trigger system for it and the laser beam it shoots is weird, to solve this, we need to replace CLNE with powered clone (PCLN from the powered materials category), this element can be switched on and off using PSCN and NSCN (from the electronics section).
GIF: http://imgur.com/kITzcNh.gif
Note: The thickness of the PCLN rectangle is only 2 pixels in this example, if you add another layer, it will shoot in more than one direction, this can be solved by using VOID from the special section as a body for the laser instead of DMND, this removes any particle that touches it.

You can change the temperature of the laser beam by making it touch something that is higher in temperature.
GIF: http://imgur.com/VkCWBoe.gif
Note: Make sure PSCN and NSCN aren't effected by the high temperature created by the plasma so that they don't melt, you can use something that isolates heat for that, I only made a small gap.

You can change the speed of the laser beam using accelerators (ACEL) and decelerators (DCEL) from the force category.
GIF: http://imgur.com/3Siruzx.gif

You can also change the colour of the laser beam using filters (FILT from the solids category). If you heat it up, it will change its colour.
GIF: http://imgur.com/Ah21JRT.gif

I hope this was helpful, if you want to learn the keyboard shortcuts I used (like the ones that create squares and lines), check out this simple interactive tutorial made by @boxmein https://www.boxmein.net/tpt/tptkeys
Also if you want to learn how something is done in a creation made by someone, you can pause the game, press D to make more things appear in the HUD and disable the deco quick option by clicking the D button from that section above the element categories or press ctrl+b.

Oops, the first gif isn't complete for some reason, here is an updated one http://imgur.com/t10idVt.gif

gobble gobble
gobble gobble
    gobble gobble
    gobble gobble
        gobble gobble gobble