Complex Addition Arithmagon
Simple task: 
- Hide the blue boxes, show the yellows.
 - Add complex numbers of your choice in the yellow input boxes.
 - Calculate the missing complex numbers in the blues (they are the sum of the yellow pair they are between)
 - Check your answers by showing the blues.
 
- Hide the yellows, show the blues.
 - Click on 'Do Reverse' in the top left.
 - Enter complex numbers of your choice in the blue input boxes.
 - Calculate the missing complex numbers in the yellows.
 - Check your answers by showing the yellows.