Scratch

Well, Archmage has a whole thread, but what the heck. I'll try. First, make variable ScrollX

This on background with:

[blocks]<when green flag clicked>[/blocks]
[blocks]<forever if><key[right arrow  ]pressed?>[/blocks]
[blocks]<change{ scrollx }by(-5[/blocks]


blocks]<when green flag clicked>[/blocks]
[blocks]<forever if><key[left arrow  ]pressed?>[/blocks]
[blocks]<change{ scrollx }by(5[/blocks]



And on Sprite Zero (Name it that):


[blocks]<when green flag clicked>[/blocks]
[blocks]<forever>[/blocks]
[blocks]<set x to((( <{scroll  }> <+>(( 480 <*> 0 ))  ))[/blocks]


And for ever other background sprite, multiply 480 by 1 bigger number. For Example:

Above is sprite Zero, this is sprite One:


blocks]<when green flag clicked>[/blocks]
[blocks]<forever>[/blocks]
[blocks]<set x to((( <{scroll  }> <+>(( 480 <*> 1 ))  ))[/blocks]