How to download and setup shadertoy
Open terminal and run command
                                            git clone https://github.com/reindernijhoff/shadertoy.git
                                        
                                        git clone is used to create a copy or clone of shadertoy repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with shadertoy https://github.com/reindernijhoff/shadertoy/archive/master.zip
Or simply clone shadertoy with SSH
                                            [email protected]:reindernijhoff/shadertoy.git                                    
                                    If you have some problems with shadertoy
You may open issue on shadertoy support forum (system) here: https://github.com/reindernijhoff/shadertoy/issuesSimilar to shadertoy repositories
Here you may see shadertoy alternatives and analogs
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