Isn't it Hypothetical???
Details and assumptions:
"B-1" means that Blue color emerges out of the prism along the ray 1 and likewise.
Ray 4 is the extension of line segment OE.
In the figure, I haven't made how the beam is refracted inside the prism.
Note: Since there is no option for "Optics" in the topic section, I have put this question under "Mechanics".