>>58432738
>Meganium
This is clearly based on a 'Y' shape. Look at the antenna and head, they resemble a 'Y'. The long neck of the meganium resembles the stem of the Y with the antenna being the two points.
>Emboar
This is an 'X'. The Two large flames on its chest resemble the top two points of the 'X' shape, with the legs being the lower two points of the 'X'
>Feraligatr
This is a 'Y'. Facing the front and with it's jaw closed, the false 'arms' of the totodile pointing up give the resemblance of a letter 'Y' shape.

All in all, these megas clearly Xactly resemble an X and Y, because Y not?