Since I'm no shader expert maybe anyone has a clue.
ERROR: 0:16: '*' : wrong operand types no operation '*' exists that takes a left-hand operand of type 'attribute 4-component vector of float' and a right operand of type 'const 2-component vector of float' (or there is no acceptable conversion)
ERROR: 0:16: 'assign' : cannot convert from 'attribute 4-component vector of float' to 'varying 2-component vector of float'
ERROR: 0:16: '*' : wrong operand types no operation '*' exists that takes a left-hand operand of type 'attribute 4-component vector of float' and a right operand of type 'const 2-component vector of float' (or there is no acceptable conversion)
ERROR: 0:16: 'assign' : cannot convert from 'attribute 4-component vector of float' to 'varying 2-component vector of float'

