Creating a working model to represent different types of triangles using cardboard, colored paper, two holes, and rotation with a nut and bolt can be a hands-on and interactive project.

Here’s a simple DIY project for a rotating triangle model:

**Materials Needed:**

- Cardboard
- Colored paper
- Ruler
- Pencil
- Scissors
- Nut and bolt
- Hole puncher or drill
- Glue or tape
- Markers

**Types of Triangles to Represent:**

- Equilateral Triangle
- Isosceles Triangle
- Scalene Triangle
- Right Triangle
- Acute Triangle
- Obtuse Triangle

**Steps to Create the Rotating Triangle Working Model:**

**Step 1: Prepare the Base:**

- Cut a large piece of cardboard to serve as the base for your working model.

**Step 2: Draw and Cut Triangles:**

- Draw and cut out each type of triangle from colored paper. Make sure the triangles are large enough to be visible on the cardboard.

**Step 3: Attach Triangles to Cardboard:**

- Glue or tape each triangle onto the cardboard, leaving space between them.

**Step 4: Create Holes:**

- Use a hole puncher or drill to create a hole near one vertex of each triangle. Make sure the holes are aligned.

**Step 5: Nut and Bolt Assembly:**

- Assemble a nut and bolt through the holes of the triangles. Tighten the nut, allowing the triangles to rotate.

**Step 6: Label the Triangles:**

- Label each triangle with its respective type (e.g., Equilateral, Isosceles, Scalene, Right, Acute, Obtuse).

**Step 7: Display and Demonstrate:**

- Set up your rotating triangle working model at the exhibition table.
- Rotate the triangles using the bolt to demonstrate different types of triangles.

This rotating triangle working model provides an interactive and dynamic way to showcase different types of triangles using a nut and bolt mechanism.