Leyline of Lightning can you pay more then 1 to do more then 1 dmg?

[killarobot]

can you pay like 5 if you have Leyline of Lightning to do 5 damage to player or can you play only 1

also what if you have 2 Leyline of Lightning in play will you be doing double dmg for each 1 you pay?

[Zidarose]

You may pay the {1} only once per spell.

It would take multiple instances of Leyline of Lightning to do pay more to get the extra damage as each instance can only activate once.

To double damage you need something like furnace of rath