A Kinetic Beast Finalisation Part 1

After a tedious process of taming the beasts, we finally understood how our designated animals interact, individually and together. Minjee and I came together with our final project-  

The Purifier.

Do check out Minjee’s OSS for part 2 on our explorations, challenges, and future projections. https://oss.adm.ntu.edu.sg/minjee001/croc-plover-behind-the-scenes/

The link redirects to our PDF to summarise the entire project:


final submission

Product Brief:  Our kinetic installation named The Purifier, is an amalgam of the quiet aggression of a crocodile and the perky routines of a plover bird.

It is a moving platform constructed with a Japanese “deer fountain”  pivot that directs hot water down a scaly acrylic board brushed with thermo-chromatic paint. 

The pivot represents the plover bird‘s plucky energy of pecking incessantly at the crocodiles‘ teeth. The slanted scale mimics the body of a crocodile,  slowly and gently floating on water while being cleaned up by the plover bird. It hides its sharp teeth within its scale exoskeleton.

Meanwhile, both animals share an affinity with warm temperature, where the plover bird uses the heated water to lay eggs and the crocodile uses its back scales to source out heat. We chose to represent this common trait with colours that changes according to temperature. And hot water is a concept that is  physically and aesthetically charged with energy.

The process of starting this installation starts from funnelling hot water down onto the peak of the pivot, which the water accumulates weight against the balance point and eventually pours out. The hot water brings the “plover bird” down to the “crocodile” and trails down the slope. The hot water seeps down the acrylic, turning the acrylic from dark green to yellow as it moves along protruding edges, slithering like a crocodile.

The hot water sliding off the acrylic propels the installation away.


                         添 水                          

movement of pivot
colour changing to heat

ocean purifier

After much consideration, we realised that there was one obvious function that this installation could be broken down into- Cleaning. 

The very fundamental relationship between the crocodile and the plover bird stems from the plover bird eating flesh off the crocodile who just lies in the water stale and awaiting for a chance to pound. This could not point further than an ocean purifier.

The Ocean Purifier is a futuristic device that is self functioning, afloat the ocean.It moves around the ocean without manual control, filtering the ocean clean of pollution. Dirtied water spirals down the polygonal funnel, splitting into the magnetic pivot filters, picking up metal scraps. The water then moves down into the jagged base,  where bigger chunks of junk are retained. Technology is advanced and the jagged base releases a non-toxic chemical that purifies the water. It changes colour the moment water touches it, becoming visually stunning whilst in a concept that is often seen “dirty”

To accentuate this idea and installation, many explorations were done and those can be found on Minjee’s OSS. The process of making this installation functional was tedious and that will be explained below.

Plover’s Pivot

Minjee started out with a great abstract representation of the plover bird that funnels water as it moves along a pivot, much like a water wheel. We later found out that this was a concept commonly known as a “deer fountain” or sōzu which is commonly used to frighten crop pests away. We took a while to understand and harness the concept of balance, our attempts are shown below. 


more failed attempts
successful attempt

We realised that this entire structure is based on balance and weight. The pivot is a beam lined with an off-centred balance thats heavier behind. This creates a default position of perking upwards like a bird shown in the sozu shown below. The water’s weight when accumulating on the beam pushes it downwards and releases the water. We realised the reason why our model did not work efficiently was because it lacked space below the beam. This meant that the beam lacked space for the pivot to rotate down and move up, losing ability to gain momentum. We picked up on it and adjusted the model’s height accordingly.

perspective view

Crocodiles Scales

The crocodiles’ scales were less restrained with technicality, since it is just mainly acrylic shards with thermo chromatic paint. The crocodiles’ scales thus changes colour according to the heat. Our initial model was abstracted scales that rises with water, which we eventually turned into a flat plane where water floated on, which is further abstracted into protruding spikes. The spikes allow the water to flow around in a slithering pattern, instead of one smooth flow.

initial colours- dark green
heated colour- yellow

On the day of presentation, the scales turned yellow 1 minute into standing outside. This immediacy and adjustment to heat is representative of this dynamic ability of the crocodile.

perspective view

The shards are placed at an angle that allows the water to flow in a slithering position. They are also placed at an angle such that the water can flow over.

Initially the thermo-chromatic paint was lined over the plover bird instead of the crocodile. It was meant to have the bird change colour when the hot water funnels down. Instead, we decided that the water flowing over the crocodile’s back would be more visually engaging.

We realised that the thermo-chromatic paint (which is actually heat-sensitive nail polish) turns transparent when heated. We had an issue earlier on as we realised that the black paint turns white, which is coincidentally the colour of the plover bird model.

plover changing colours


To further elaborate on the movement of the animals within this installation:

The crocodiles’ movement is represented as the slithering motions of the trailing water hot water, leaving a line of yellow amongst the dark green acrylic. It is also represented in the floating motion of how a crocodile hunts, snout above the water. More subtly is the representation of having teeth underneath the acrylic board, which will be discussed further in part 2.

The plover bird’s movement is the pecking action of picking out meat from the crocodiles teeth, just a routine action of falling up and down.


A crocodile prototype

In the eyes of a crocodile

With the information we have from our research process, we attempt to create a model that moves in the eyes of the kinetic beast, much like Theo Jansen’s Strandbeests.

Breaking down the movements of a crocodile, I summarised it into two main movements: the slithering pattern inherent in its streamline body as well as the concurrent movement of opposite front leg and hind leg.

Refer to the diagram from the previous research process.

Slithering starts with floating in the middle of the water, then paddling
Concurrent movement of opposite legs





The first prototype attempts to investigate the slithering pattern inherent in a crocodile’s streamline body. This movement is only allowed with the flexibility of the pivotal mechanisms of the spine. Hence, I tried to apply it to the model by building it into two sections.

Isometric drawing of model



Explaining the process of the machine, I used a wind-up mechanism to create movement. The rubber band is tied to the turnable rig that extends into the wheel. The rubber band is tied tightly onto the rig as well. Hence, when the rubber band is turned by the rig, it converts the kinetic energy of the spin into potential energy stored in the elastic band, shown in the diagram above. When released, the prototype mimics a wind up toy or pull back motor, and moves forward with the rubber band’s potential energy released as kinetic energy. The movement forward is enhanced with the paddles inserted into the wheel of the prototype. The loose spine connecting the two sections help to create the slithering movement of a crocodile.


Test drive

The prototype did not work well as the foam was too light. This made the prototype float above the water, resulting in a weaker albeit moving motor. The prototype only moved a short distance and did not slither as much as I envisioned. I added wood panels to the bottom in later adjustments.

top view
side view



I realised that the current equipment I have set up for the wind up mechanism is too weak, despite trying out different rubber bands of different elasticity. I tried latex rubber band, generic red rubber bands and hair band as well. Hence, I decided to change up into something else, and maybe work on the second movement- concurrent movement of opposite front leg and hind leg.

With the set-up above, I utilised gears to create different directions of movement. With the central gear acting as the main source of movement, it creates different direction between the top left leg- hind right leg and the top right leg-hind left leg. This concurrent movement of gears mimics how a real crocodile moves. This set-up would be useful if its morphed with the first prototype’s streamline shape, using either elastic band or wind energy to power the motor.

1st attempt
2nd attempt


In the end, I was sick and didn’t attend class. However, Minjee did update me on the feedbacks given by Cheryl. Hence, we listed the characteristics down and planned how our final work would encompass, which are: Bobbing up and down the water like a crocodile, pecking of the plover bird and changing of colours with the temperature.  Do take a look at Minjee’s OSS for the understanding of her plover bird prototype, in comparison for the mutualism relationship it shares with a crocodile.