Register, register, register-- if the stencil doesn't already have a little hole punched in each of the 2 lower corners, make one. Mark a tiny dot on the wall there where the hole is, in a color that will not show from a distance or that can become part of the pattern later. Next pass, when you start the next color, be sure the stencil hole hits that dot. You will be all lined up. More accurate with 4 dots, 1in each corner. The dot is called a registration mark, from the printing industry so diff plates/negs line up in color printing. When your newspaper looks funny and blurry in the color pix, the REGISTRATION (aka REGISTER) is off.

~S~