You have 1 inch cubes you want all there dimensions (x,y,z) of the cube to equal 2. So I put 2 cubes together [][]and that means that my x dimension is 2. Then I add one above it to make y equal two []
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in order to make a square (when you look at it from the top) i need to add another square to the top right [][]
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so now I have a cube that has dimensions of 2,2,1 ans so far I have used 4 boxes so now I need to make my z dimensions equal to so I stack two sets of these 4 cubes on top of each other.
from the top
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from the side
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I hope this makes sense if not just use dice or any other small cubes you have.
As for the bullet question both bullets will hit Earth for the most part at the same time because gravity effects each bullet equally.
Please clarify the second question.