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 classic fractal created through a recursive geometric process.
- We start with a single solid equilateral triangle (Step 0).
- At each subsequent step, we connect the midpoints of the sides of every existing solid triangle, creating smaller congruent triangles, and remove the central upside-down (inverted) triangle.
- Repeating this process infinitely forms the Sierpinski Triangle.
Step 1 · Step 0 — Initial Solid Triangle
Start with a single solid equilateral triangle.
Step 2 · Step 1 — First Transformation
Connect the midpoints of each side of the triangle. This divides the original triangle into smaller congruent equilateral triangles. Remove the central inverted triangle, leaving smaller solid triangles at the corners.
Step 3 · Step 2 — Second Transformation
Repeat the same procedure for each of the remaining solid triangles from Step 1. Connect their midpoints and remove each central inverted triangle. This leaves smaller solid triangles.
Step 4 · Repeating the Pattern
Continuing this process infinitely by repeatedly subdividing every remaining solid triangle into and removing the central triangle produces the Sierpinski Triangle fractal.
- Step 0: Start with a single solid equilateral triangle.
- Step 1: Connect midpoints to divide the triangle into smaller triangles; remove the central inverted triangle ( solid triangles remain).
- Step 2: Repeat the process on each remaining triangle to get smaller solid triangles.
- Step 3 and beyond: Continue recursively removing the central inverted triangles.
- Removing the Wrong Triangles: Removing the corner triangles instead of the central inverted triangle.
- Miscalculating Remaining Triangles: Forgetting that at step , the number of remaining solid triangles is (Step 0: , Step 1: , Step 2: , Step 3: ).
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 step of the shape sequence that leads to the Koch Snowflake.
Find the perimeter of the shape at the 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) , , and
(ii) , , and
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?