I remember organising the colours of the rainbow in columns. In the way that I did, I could create the word RAINBOW from certain letters in each word, indicated by the columns they were each placed in. However, I forgot how it worked, and I can only remember four colours in each of their position — I don't know which position each of the other three colours belong to. I have marked those remaining positions that the colours need to go in, with hyphens of a quantity matching to the number of letters in its neighbouring colour of the same column.
Red ------ Green Indigo Orange ----- ------
Which colour of the remaining three goes in which position to achieve the word RAINBOW in the way previously described?
No hints! You have been given more than one ;)