OTL is a stick figure of a person on all fours. O= head, T = arms on the ground, and L = legs. The lowercase form is orz. This emoticon can be used interchangeably with *worship* which simply means that you are grateful to whomever you present the emoticon to.
exists and is an alternate of . Nuclear fusion is a nuclear reaction, not a chemical reaction. In nuclear fusion, the nuclei of atoms combine in order to form new atoms (hence the term nuclear reaction). This type of reaction is mainly concerned with the movement of protons and neutrons.
The  most common example of nuclear fusion is when two types of (known  as isotopes of) hydrogen fuse together to create helium. The  isotopes of hydrogen deuterium and tritium fuse to create helium.  Deuterium contains one proton and one neutron and tritium contains  two neutrons and one proton.