visual   =~ x2 + x1 + x3
             textual  =~ x4 + x5 + x6
             speed    =~ x7 + x8 + x9 
 
 textual ~ visual + speed
 visual ~  speed

F1=~  + general + picture + reading + vocab

visual   =~ x2 + x1 + x3
             textual  =~ x4 + x5 + x6
             speed    =~ x7 + x8 + x9 
 
 textual ~ visual 
 visual ~  speed

visual   =~ x2 + x1 + x3
             textual  =~ x4 + x5 + x6
             speed    =~ x7 + x8 + x9 
 
 speed ~ visual
 visual ~ textual

visual   =~ x2 + x1 + x3
              textual  =~ x4 + x5 + x6
              speed    =~ x7 + x8 + x9

visual   =~ x2 + x1 + x3
             textual  =~ x4 + x5 + x6
             speed    =~ x7 + x8 + x9

visual   =~ x2 + x1 + x3
             textual  =~ x4 + x5 + x6
             speed    =~ x7 + x8 + x9 
 
 textual ~ a*visual + b*speed 
 visual ~  c*speed
  
  indirect := a*b
  total := indirect + c

14 ability tests from Holzinger-Swineford