I was asking myself if it is possible to clone a coin 1:1, mine a lot of coins and sell them as real coins

For example i copy the sourcecode of SC nd mine those coins on my Laptop, since Im the only 1 mining this (clone, copy) Iit would be easy to mine lots of them

What mechanism prevents that from happening??

We all know the Federal reserve Bank has the right to print Dollars and in the Bitcoin System everyone can mine Bitcoin but what stops me -besides the knowledge- from cloning those coins and kind of faking them

Has anyone ever tried that??