Assemblies and methods for applying painter's tape to a wall for painting stripes thereon wherein the assembly has a first elongated body with a first straight outer edge, a second elongated body having a second straight outer edge with a substantially transparent body and having a tape width guide marking substantially along the elongated body with a plurality of elongated markings parallel to the second straight outer edge, two or more arms each having ends rotatably coupled to the first and second elongated bodies respectively, each of the arms being spaced apart of another and coupled at different positions of the elongated bodies, and a coupling mechanism rotatably coupling an arm to one of the elongated bodies and having a locking feature selectively fixing the angular position of the coupling mechanism and preventing rotation of the rotatably coupled arm relative to the coupled elongated body.

Disclosed is a stair tread template ruler, including a main ruler body, and two side ruler bodies. Either of the side ruler bodies is provided with a sliding member that can slide in a reciprocating manner, and the main ruler body is hingedly connected to the sliding members. The two side ruler bodies are arranged at both ends of the main ruler body, and the main ruler body and the two side ruler bodies cooperate to contour a space such as a staircase. The two side ruler bodies are connected to the main ruler body, the sliding members can slide to meet various use requirements, and the main ruler body is rotatably connected to the sliding members, which facilitates adjustment of a relative angle, meets user needs, and simplifies folding and storage. The main ruler body has a multi-segment structure, and each segment is slidably connected to another.