I think it can 1, 3, 10, 100, 1000 fold or any number really. I think it depends on the caster, the ritual, their intentions, any magickal beings involved and so on.
Remember seeing those cartoons where somebody takes a snow ball and rolls it down a hill and as it goes it starts to pick up more and more snow making a larger and larger ball? Well thats how I feel about magick. Only there are a variety of things that make the snow ball grow. Intention is one. If one intends to create a big impact than thats one factor. The next is the amount of energy actually put into the magick. Another is if one appeals to alterior source for magickal change i.e. Gods/esses, faires, dragons ect ect. These sources can make change in a big way that causes a lot of unintended consequences. But I think that only happens if the magician makes a crittical error in the workings - they omit a required sacrifice or don't have clear intentions for example. Then there is also the duration of the magick. A cartoon snow ball rolling down a hill will grow and grow until it falls off a cliff or is stopped my something. Magick can have a similar affect. Longer magick is meant to work the higher degree the consequences will be, positive or negative. Remember consequence is should not be understood only as a means of karmic retribution. Consequence simply means the aftermath of a magickal working - which could be either good or bad. Then this gets even more complicated because sometimes we think something bad happens and its a karmic backlash when in reality the "suffering" felt could be necessary for positive growth. And visa versa as well something good happens to build one up to be able to handle something bad yet to transpire.
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