Vectors - direction + magnitude
     unit vector - vector of length
                                              |                 ^               <a, b, c>
          > a               \           /> a  |                 |               <1, 0, 0>
         /     <             \         /      |               y |               <1, 0, 1>
        /       \             \       /       |        vector j |
       > a       \             > -a           |                 |
      /       <---- 2a                        |                /.----------->     i     = <1, 0, 0>
     /                                        |               /        x          k     = <0, 0, 1>
                        />\                   |  vector k    /        vector i    i * k = 1*0 + 0*0 + 0*1 = 0
                     a /   \                  |             <
                      /     \> b              |              z
                      ------>                 |
                        a+b                   |
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          Dot product - scalar

          vector V1 = <a1, a2, a3>
          vector V2 = <b1, b2, b3>                                   /|
          vector V1 * vector V2 = a1b1 + a2b2 + a3b3         sqrt(2)/ |
          vector V1 * vector V2 => S = |V1||V2|cos(Theta)          /  | 1
          |V1| = sqrt(V1*V1)                                      /   |
               = sqrt(a1^2 + a2^2 + a3^2)                        /-----
                                                                    1
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          Making a unit vector (in the some direction as another vector)

          V3 / |V3| = <1/V2, 0, 1/V2> = <sqrt(2)/2, 0, sqrt(2)/2>
                                      = sqrt((sqrt(2)/2)^2 + 0^2 + (sqrt(2)/2)^2)
                                      = sqrt(2/4 + 0 + 2/4)
                                      = 1
          V3   = <1, 0, 1>
          |V3| = sqrt(2)