code: function angle(a, b) {
      var tempA = fromValues(a[0], a[1], a[2])
      var tempB = fromValues(b[0], b[1], b[2])
   
      normalize(tempA, tempA)
      normalize(tempB, tempB)
   
      var cosine = dot(tempA, tempB)
  
      if(cosine > 1.0){
          return 0
      } else {
          return Math.acos(cosine)
      }     
  }
docs: Get the angle between two 3D vectors
  @param {vec3} a The first operand
  @param {vec3} b The second operand
  @returns {Number} The angle in radians