Question 1
Draw the initial few steps (at least till Step 2) of the shape sequence that leads to the Sierpinski Triangle.

The Sierpinski Triangle is a fractal made by repeatedly removing the middle part of triangles.
Step 1 — Initial Shape
We start with a basic shape.
Let us take one solid equilateral triangle.
This is our first step, called Step 0.

Step 2 — First Transformation
Now, let us change our triangle.
We find the middle point of each side.
Connect these midpoints with lines.
This creates four smaller triangles inside.
One central triangle points downwards.
We remove this central triangle.
Three smaller solid triangles remain.
These are at the corners.
This is Step 1 of the process.

Step 3 — Second Transformation
We repeat this for each remaining triangle.
Take each of the three solid triangles from Step 1.
For each, find the midpoints of its sides.
Connect these midpoints to form a central triangle.
Remove this central triangle from each.
This leaves nine even smaller solid triangles.
These are at the corners of the previous three.
This is Step 2 of the construction.

Step 4 — Repeating the Pattern
We can continue this process forever.
Each time, we take every solid triangle.
We divide it into four smaller ones.
Then, we remove the central part.
Repeating this creates the Sierpinski Triangle.
It is a beautiful fractal pattern.
Answer
(i) Step 0: Start with a single solid equilateral triangle. (ii) Step 1: Divide the triangle into four smaller equilateral triangles by connecting the midpoints of its sides. Remove the central inverted triangle. (iii) Step 2: For each of the three remaining solid triangles, repeat the process: divide it into four smaller triangles and remove its central inverted triangle. (iv) Step 3: Continue this process of dividing each solid triangle and removing its central part.
More questions in FIO
Draw the initial few steps (at least till Step 2) of the shape sequence that leads to the Sierpinski Triangle.
Find the number of holes, and the triangles that remain at each step of the shape sequence that leads to the Sierpinski Triangle.
Find the area of the region remaining at the th step in each of the shape sequences that lead to the Sierpinski fractals. Take the area of the starting square/triangle to be 1 sq. unit.
Draw the initial few steps (at least till Step 2) of the shape sequence that leads to the Koch Snowflake.
Find the number of sides in the nth step of the shape sequence that leads to the Koch Snowflake.
Find the perimeter of the shape at the nth step of the sequence. Take the starting equilateral triangle to have a sidelength of 1 unit.
Figure it Out
- Which of the following are the nets of a cube? First, try to answer by visualisation. Then, you may use cutouts and try.
A cube has 11 possible net structures in total. In this count, two nets are considered the same if one can be obtained from the other by a rotation or a flip. For example, the following nets are all considered the same —
Find all the 11 nets of a cube.
Draw a net of a cuboid having sidelengths:
(i) 5 cm, 3 cm, and 1 cm
(ii) 6 cm, 3 cm, and 2 cm
Observe the front view, top view and side view of the different lines in Fig. 4.6. Is there any relation between their lengths?
Find the front view, top view and side view of each of the following solids, fixing its orientation with respect to the vertical, horizontal and side planes: cube, cuboid, parallelepiped, cylinder, cone, prism, and pyramid. If needed, see the next problem for clues.
Match each of the following objects with its projections.
Draw the top view, front view and the side view of each of the following combinations of identical cubes.
Imagine eight identical cubes, glued together along faces to form the letter 'C'.
Which solid corresponds to the given top view, front view, and side view?
Solids to choose from:
Using identical cubes, make a solid that gives the following projections:
Find the number of cubes in this stack of identical cubes.
What are the different shapes the projection of a cube can make under different orientations?
In addition to the 5 ways shown in Fig. 4.8, are there any additional ways of gluing four cubes together along faces? Can you visualise and draw these as well?
Draw the following figures on the isometric grid.
[Hint: It may be useful to determine whether the edge to be currently drawn — say, along the height — goes from down to up or up to down. Accordingly, draw the line segment on the grid either in the direction of the height axis or opposite to it.]
Is there anything strange about the path of this ball? Recreate it on the isometric grid.
[Hint: Consider a portion of this figure that is physically realisable and identify the 3 primary directions.]
Observe this triangle.
(i) Would it be possible to build a model out of actual cubes? What are the front, top, and side profiles of this impossible triangle? (ii) Recreate this on an isometric grid. (iii) Why does the illusion work?