# MATLAB Programming/Bonus Chapters/MATLAB Easter Eggs

MATLAB is one of the very few professional software in the market now that included Easter Eggs in their products.
Here are the few known undocumented demo functions: Just type these commands and have a look for yourself:
All of this Easter Eggs were tested on MATLAB R2020a ( in not alphabetical order)
Have fun playing with the known Easter Eggs~ Note: To view the source code, use edit function followed by command name

### Working Easter Eggs

| Command | Description | Picture/Examples |
| cruller | Construct a cruller by revolving the eccentric ellipse defined by the function XYCRULL. | Cruller Render |
| date | Returns date as in dd-mmm-yyyy format | 08-Aug-2022 |
| sldemo_fuelsys | Simulations of Fault-Tolerant Fuel Control System Dashboard | |
| funtool | A interactive graphing calculator that manipulates functions of a single variable. | |
| sf_aircraft | Simulate the fuel injection system in aircraft | |
| sf_newtons_cradle | Simulate Newton's cradle | |
| teapotdemo | A demo that uses the famous Newell teapot to demonstrate MATLAB graphics features. | |
| teapotGeometry | Data generates vertices, faces, and colors that represent the surface of the infamous Utah teapot. | |
| graf3d | Demonstrate Handle Graphics for surface plots in MATLAB. | |
| earthmap | Globe to represent the Earth's topography | |
| soma | Precomputed solutions to Piet Hein's soma cube | |
| somasols . | Generate complete solutions to the soma cube | |
| clock | Returns a six element date vector containing the current time and date in decimal form: [year month day hour minute seconds] | 1.0e+03 * 2.0220  0.0080  0.0070  0.0230  0.0360  0.0192 |
| taxDemo(income) | Calculate the tax on income. | |
| logo | Plot the L-shaped membrane logo with MATLAB(R) lighting. | Matlab Logo |
| membrane | Plot a 3-D colored surface of MATLAB(R) logos | |
| spy | This function is actually to use to visualize sparsity pattern. When no input of argument is given, it will generate a image of the dogs. If typed in version prior to Matlab R2011a, it will show character White Spy from comics Spy vs. Spy | |
| life | This is MATLAB's simulations of Conway's Game of Life. Whether cells stay alive, die, or generate new cells depends upon how many of their eight possible neighbors are alive. By using sparse matrices, the calculations required become astonishingly simple. | |
| truss | Animation of a bending bridge truss. This demo animates 12 natural bending modes of a two-dimensional truss. | |
| vibes | This demonstration solves the wave equation for the vibrations of an L-shaped membrane. | Matlab Vibes |
| makevase | Generate and plot a surface of revolution. The body-of-revolution corresponding to that line is plotted using the SURFL command. | MATLAB EASTER EGGS MAKEVASE |
| sf_cdplayer | Simulink model simulate the CD player. | |
| xpbombs | Shows a game of Minesweeper , There are 13 bombs hidden in the mine field. | MATLAB Easter Eggs |
| lorenz | Plot the orbit around the Lorenz chaotic attractor. | |
| travel | This demo animates the solution of the "Traveling Salesman" problem. (Limited to cities inside USA) The problem is to form a closed circuit of a number of cities while traveling the shortest total distance along the way. | |
| fifteen | Shows a game of fifteen game puzzles A sliding puzzle of fifteen squares and sixteen slots. Solve the puzzle by sequentially lining all fifteen squares up, leaving the last square empty. | |
| bucky | Connectivity graph of the Buckminster Fuller geodesic dome. (shows 60 coordinates) | |
| sf_spectrum_analyzer | Simulation of measuring the Frequency Response of a System | |
| census | Shows the extrapolated predicted populations in the United States | |
| sf_angle_events | Simulate cranking and power output | |
| ex_guide_timergui | Execute graphic updates at regular intervals | |
| quivdemo | Superimpose QUIVER on top of a PCOLOR plot with interpolated shading. | |
| sf_elevator | Simulations of elevators inside 9 storey buildings. | |
| penny | Shows 3D render of a USA penny | |
| matlab.ui.internal.toolstrip.Icon.showStandardIcons | Shows allstandard icons | |
| knot | Compute the parametric representation of tube-like surfaces and displays the tube with SURF. | |
| spharm2 | This example shows how spherical harmonics, which are spherical versions  of Fourier series, can be used to model the free oscillations of the  Earth. | |
| eml_asteroids | Play a game of Asteroids | Asteroids in MATLAB |
| eml_fire | Simulations of burning fire | |
| sf_tetris2 | 'j', 'l' -- move  left and right 'i', 'k' -- rotate left and right SPACE  -- drop 'p'   -- pause 'q'   -- quit | |
| ballode | Simulate a demo of a bouncing ball. | |
| batonode | Simulate the motion of a thrown baton. | |
| sf_semantics_hotel_checkin | Simulate Hotel Checkins | |
| sf_traffic_light | Simulating traffic lights at intersections | |
| sf_fitness | Simulate the smartwatch | |
| klein1 | This example shows how to generate a Klein bottle. A Klein bottle is a nonorientable surface in four-dimensional space. It is formed by attaching two Mobius strips along their common boundary. | |
| xpklein | This example shows how to display a self-intersecting Klein bottle.  A Klein bottle is a nonorientable surface in four-dimensional space. It is formed by attaching two Mobius strips along their common boundary. | |
| brussode | Surface plots of brusselator | |
| why | Randomly generated answers to life , universe and everything | |
| iburgersode / burgersode | Burgers' equation solved as implicit ODE system | |
| sf_stickslip | Stick - slip friction simulations | Sf stickslip - Simulink |
| sfediticon | Simulink icons that enable to create basic 16 * 16 icon editor | |
| amp1dae | Stiff differential-algebraic equation (DAE) from electrical circuits | |
| taylortool | A Taylor Series Approximation calculator | |
| sf_climate_control | Simulate an environmental climate control (Temp and humidity) for a chamber | |
| tori4 | This example shows how to generate four linked unknotted tori by rotating four off-center circles. | |
| ardemo | Interactive axes properties demonstration | |
| rlc_gui | Interactive GUI showing the relationship between the physical parameters of common RLC circuits and the time and frequency responses of those circuits.     * Low-pass RLC network     * High-pass RLC network     * Band-pass RLC network     * Band-stop RLC network | |
| sf_security | Demonstrations of security system of door, window and mention sensor in a home | |
| sf_server | Display random numbers to serve the assigned clients | |
| step | Shows a randomly generated stable Transfer Function Model | |
| imagesc | Shows the images of a boy. To correct it , into correct orientation , type imagesc colormap(gray(32)); axis ij image off; | |
| wernerboy | This example shows how to create Boy's surface | |
| transpdemo | This example shows how to modify the transparency value for graphics objects to reveal structure that is obscured with opaque objects. | |
| sf_car | Simulate car braking and throttle | |
| sf_yoyo | Simulate yoyo up and down and the energy | |
| sf_boiler | Simulation of temperature controller of boiler | |
| eml_aero_radar | Radar demo to estimate aircraft position using Kalman Filters | |

### Untested Easter Eggs

sf_gui
sf_mandelbrot_fixpt
eomfun - Old
eigshow - Old
imagesAndVideo - Shows an moving images of rocket flying to the space
imagesc(hot) / imagesc(cool) / imagesc(hsv) - ???
old_sf_car
eml_clock
uitabledemo - ???
sf_tictacflow - SIMULINK project to simulate a game of Tic Tac Toe against AI
wrldtrv - Show great circle flight routes around the globe
xpquad - ???
xpsound - ???
Not working
sfbus_demo
sf_moore_traffic_light
sf_bidder
sf_power_window
NOTE: If there are any readers who knows what is the ??? easter eggs represent, you may kindly add in.

### References

* ↑ https://blogs.mathworks.com/steve/2006/10/17/the-story-behind-the-matlab-default-image/
* ↑ https://web.archive.org/web/20210615225906/https://undocumentedmatlab.com/articles/image-easter-egg
* ↑ https://web.archive.org/web/20210803075033/https://undocumentedmatlab.com/articles/spy-easter-egg-take-2
* ↑ https://web.archive.org/web/20210123224206/https://ashanpeiris.blogspot.com/2014/12/matlab-easter-eggs.html
* ↑ https://www.testingdocs.com/in-built-graphical-demos-in-matlab/