Overlay description ...
static Overlay CreateGraphical(int x, int y, int slot, bool transparent)
Creates a screen overlay containing a copy of the image from SLOT in the Sprite Manager. The image is placed at (X,Y) on the screen (these are screen co-ordinates, not room co-ordinates).
static Overlay CreateTextual(int x, int y, int val, FontType font, int big, string buf)
static Overlay CreateTextual(int x, int y, int val, FontType font, int big, string buf, string bufferID)
Create Text Overlay. Also pass in buffer ID so it can be re-used.