visually impaired
teaching aids
CAD modeling
3D printing

In development
  1. Ideation
  2. In development
  3. Final reviewing
  4. Finished


Project Aakaar is an attempt to help visually impaired (VI) students gain a fundamental understanding of geometry and inspire them to practice the subject.

Table of Contents


We have carefully designed a set of puzzles called Tactile Tangrams where standard shapes like triangles, rectangles, and semi-circles are to be combined to give a 2D representation of compound shapes. These puzzles connect simple shapes with complex structures of famous monuments. Aimed for VI students at the elementary school level, Tactile Tangrams are a fun way to infuse an intuition for geometry at a tender age. Further, we have designed a construction tool called Hexacompass, which is a VI-friendly tool for angle measurement and construction. All these tools are 3D printable, which makes them easily accessible and self-manufacturable, with the use of desktop 3D printing, a technology that is becoming more commonplace every day. We hope that our work will not only be helpful for the VI students and their teachers, but also garner interest of other designers to expand the toolkit further.


According to Kartik Sawhney, who is a disability advocate and technologist, one of the five problems that keep VI students away from STEM subjects is the scarcity of resources providing for a solid conceptual understanding of STEM for the blind. We found this problem substantiated by our experience at the schools for the blind in case of geometry, a subject that became our point of focus for the project. During our interview with one of the Teachers for Visually Impaired (TVIs) at Devnar School for the Blind in Hyderabad, India, we understood that not only it was difficult for the VI students to grasp the concepts of geometry, but it was also challenging to teach the same (read the whole conversation here[1]). While the students in the school used tactile templates to touch and register shapes, there was a lack of tools that established a relationship between different shapes and connected geometry with the observable world. Thus, there was no means to bring a natural intuition for the subject that could form the basis of a formal course in geometry. The problem is further compounded in schools where teaching aids and appropriate infrastructure are at a bare minimum. During our visit to Louis Adarsh Blind School in Warangal, India, which is a charity-run school in a dilapidated condition, we couldn’t find tactile teaching aids or even sufficient amounts of braille-printed books. This is the case with many of the schools for the blind in developing countries like India which have large populations of VI students (at least 200,000 in India alone[2]). We realized a need for easy-to-procure educational aids to help understand relationships among/between geometric shapes and the environment, and have the potential to be used for practicing geometry. We set the following parameters necessary for the designs to accomplish the objective:
  1. The designs should be easily 3D printable so that anyone with the CAD (Computer Aided Designs) files and access to even a low-quality 3D printer can print them.
  2. These aids should not go beyond the scope of the curriculum, rather supplement the topics in the curriculum.
  3. The designs should be easy to understand and tickle curiosity and imagination in the user.

Our Designs

From our experience at the school for the blind, we identified a need for tools that explained concepts of basic geometry in an attention-grabbing manner (concept building), and gave independence to the students to practice geometry (construction). As we brainstormed around these two ideas, we realized that not only they called for two different types of tools, but also applied to two different age groups of students. Therefore, we worked on the ideas exclusively and designed concept building tools for the VI students of classes 3-5, and construction tools (still in designing stage) for students of classes 5-8.

1. Tactile Tangrams

Games are known to make significant contributions to learning. Not only they open our minds to new possibilities, but they also lead to better retention of knowledge explicitly or implicitly imparted by them[3]. Our concept building tools are nothing but puzzle games inspired by Tangrams (old Chinese puzzles where seven different standard shapes are put together to form shapes of various common objects). We have named them Tactile Tangrams in which standard shapes would come and fit together to make new interesting shapes and objects. Unlike regular Tangrams, our designs include a base plate that has the required final shape engraved on it. It provides a more convenient way of completing the puzzle where the final goal could be touched and felt, and the pieces could be put accordingly into the groove. As the thickness of the pieces exceeded the depth of the groove, the resulting figure after populating the grooves correctly would be raised, giving good tactile feedback of the final result. We have designed eight of these puzzles which fall under two sets, Geometric Theme and Monument Theme, each having four puzzles.

(a) Geometric Theme

Under this theme, each of the four base plates is engraved with a rectangle, an isosceles triangle, an equilateral triangle, and a parallelogram respectively. Here the fitting pieces are two equal right-angled triangles. The final goal is to orient the pieces such that they fit into the given base plate. For example, for completing the ‘rectangle’ puzzle, the triangles are to be oriented such that their hypotenuse touch.
 Set of puzzles in Geometric Theme; two equal right-angled triangles are used to complete all the
Figure 1. Set of puzzles in Geometric Theme; two equal right-angled triangles are used to complete all the puzzles.
Geometric theme of puzzles aims to work on the following objectives:
  1. To understand the difference between different sides of the right-angled triangle
  2. To create an intuition for how orientation plays a vital role in making meaningful relationships between shapes.

(b) Monument Theme

The monument theme includes four base plates each containing tactile images of the Taj Mahal, Leaning Tower of Pisa, the Pyramids of Giza, and Eiffel Tower respectively. These tactile images have certain hollow features where the fitting pieces would go in. For example, the minarets of the Taj Mahal in the puzzle are to be completed using rectangular pieces. We have used features at multiple heights from the base plate to represent the distance of the feature from the point of view and also to bring out architectural features.
Set of puzzles in Monument theme
Figure 2. Set of puzzles in Monument theme (white ones are the fitting pieces)
Monument theme of puzzles aims to work on the following objectives:
  1. To know through touch the shape of important monuments and identify parts of them as simplified representations using geometric shapes. For example, the use of triangles for representing pyramids.
  2. To understand the concept of projection of 3D shapes. For example, the dome and minarets in the Taj Mahal, which are hemispherical and cylindrical in shape, are represented using semi-circle and rectangles.
  3. To understand the employment of geometric shapes for representing factual information, like using a wedge to depict the incline in the Leaning Tower of Pisa.
  4. To understand the connection between architectural features of different monuments. For example, we have used the same window piece for completing the windows in the Taj Mahal and the Leaning Tower of Pisa puzzles, as both the monuments have almost similar looking windows.

2. Construction Tool: Hexacompass (in design stage)

During our second visit to Devnar School for the Blind in Hyderabad in December 2019, the TVIs gave us ideas for relevant teaching aids. One idea was to make a tool that explained complementary and supplementary angles. Another idea was to design an angle measurement and construction tool. We thought of combining the two ideas into one comprehensive tool and the result was the Hexacompass. It is based on our puzzle design and contains a base plate and fitting pieces, along with a detachable compass. The tool has two major functions:
  1. To illustrate the concepts of complementary and supplementary angles using triangles of standard angles i.e. 30° and 60° measure;
  2. To aid in practical geometry with its VI-friendly detachable compass that can be used to measure angles of given objects as well as be fixed at a particular angle for construction.
Base plate of the Hexacompass
Figure 3. Base plate of the Hexacompass containing a diamond key in the center to fit the detachable compass during angle measurement.

Concept of complementary angles

The user starts by placing the first 30° triangular piece. Then they need to insert two more 30° triangular pieces into the slots to get a cumulative angle of 90°. This implies that the complement of a 30° angle is in fact 30°+30°=60°. A similar exercise can be performed for a 60° angle as well to determine that its complementary angle is in fact 30°.

Concept of supplementary angles

The user can start off by inserting one 30° triangular piece. Now, three 30°, as well as one 60° triangular piece, also need to be fit in order to achieve a cumulative angle of 30°+30°+30°+30°+60°= 180°. Multiple permutations and combinations can be used in this case and VI students can have a fun experience in trying out various such combinations.

Detachable Compass

The detachable compass includes two arms, a reference arm, and a rotating arm, with a screw-type pivot through the shoulder of both arms that can be tightened to fix the orientation of the arms and loosened during angle measurement. The reference arm, on which the rotating arm lies, has a diamond-shaped groove in the bottom of its shoulder.
Detachable Compass
Figure 4. (Top to bottom): Reference arm that fits on the diamond key of base plate; rotating arm that rotates about the bolt on the reference arm; assembly of the two arms tightened using a nut.
When the compass is placed on the base plate, a similar-shaped extrusion present in the center of the hexagon locks the compass by filling the groove. The dots on the hexagon plate can be used to determine the angle to the nearest multiple of 10°. The detachable compass can be lifted vertically from the diamond extrusion in the base plate and can be physically taken elsewhere to compare or replicate the measured angle.


Tactile Tangrams turned out to be fun and somewhat challenging for the VI students from Grade 5 at Devnar School for the Blind, Hyderabad, India. The fact that they could and must flip the fitting pieces when going from one shape (base plate) to another (Geometric Theme) was challenging for them to come by. Similarly, the Monument Theme was very helpful for VI students to understand the architectural features by the means of touch. One of the VI students at Louis Adarsh Blind School, Warangal, India, who completed the Taj Mahal puzzle gave a really encouraging comment:
“Until now, I only heard about the Taj Mahal, but from your puzzles, I have actually seen it.”


  1. Interview with teachers and VI students at Devnar Public School for the Blind, Hyderabad, India.
  2. ‘Childhood blindness in India: causes in 1318 blind school students in nine states’ by J.S. Rahi, S. Sripathi, C.E. Gilbert, A. Foster.
  3. ‘The Effect of Using Educational Games in Teaching Kingdoms of Living Things’ by M. Selvi and A.O. Cosan.
Download a more detailed PDF version of this report here.

About Us

Project Aakaar began as an Engineering Project in Community Service (EPICS) at NIT Warangal, India, when three junior engineering undergrads, Sarthak Kapoor (Materials Engineering), Shantanu Landore (Mechanical Engineering) and Daksh Parmar (Biotechnology), came together with an objective to improve education in geometry for the visually impaired (VI) students.


Feel free to download the .stl files here and print a set of Tactile Tangrams for yourself and others!

Project Aakaar by Sarthak Kapoor, Shantanu Landore, Daksh Pamar is licensed under CC BY-NC-SA 4.0