Bat Country
From Batcountry
"We can't stop here; this is Bat Country!" - H. S. Thompson
Bat Country: A Sierpinski Tetrahedron Jungle Gym is a sculpture by Gwen Fisher in collaboration with Paul Brown. It will be initially installed in the desert at Burning Man 2008.
In keeping with the Burning Man 2008 theme, "The American Dream", Bat Country is 21’ tall four-sided tetrahedron built with 384 aluminum baseball bats and 130 twelve-inch softballs. The bats form the structure’s edges; there is one softball at each vertex. Each edge of the structure measures 26’ in distance.
The structure is designed to be and intended to be climbed upon; ½” threaded steel rod runs through the axis of each bat and bolts to strong ‘joining plates’ at each vertex, to provide structural stability and facilitate transportation and onsite assembly. The total structure weighs about 2500 lbs.
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[edit] Mathematical Basis
Mathematically, Bat Country is an example of a third-generation Sierpinski Tetrahedron. Waclaw Sierpinski was a 20th century Polish mathematician who pioneered the field of fractal geometry; one of the two-dimensional fractals he described was the Sierpinski Triangle. The Triangle was one of the first shapes understood to demonstrate self-similarity: the property that its shape at any level is the same as its shape at its largest level. The Sierpinski Tetrahedron is a three-dimensional shape realizing the same concept – a tetrahedron is a pyramid with a triangular base.
Bat Country represents the idea of self similarity; the full-scale installation is an assembly of 64 small tetrahedrons. To understand the Sierpinski Tetrahedron, consider one of these tetrahedrons, made with six bats, one for each edge, and four balls, one at each corner. With four such tetrahedrons you can assemble a first-generation Sierpinski Tetrahedron (requiring 6x4 = 24 bats). If you combine four first-generation tetrahedrons, you get a second-generation tetrahedron (requiring 24x4 = 96 bats). If you combine four of these in turn, you get a third-generation tetrahedron (requiring 96x4 = 384 bats).
Note that the negative space between each tetrahedron forms a regular octahedron with eight triangular faces. The largest octahedron, in the center of the sculpture, is about 10’ high. This space, large enough for several people to stand in, serves as an inhabitable ‘room’ inside Bat Country. Self-similarly, four smaller octahedrons, one at the center of each second-generation tetrahedron, are each about 5’ high; there are also sixteen small octahedrons, one inside each of the first-generation tetrahedrons.
[edit] Alternate Views of Sculpture
Appreciating Bat Country from a visual perspective requires no mathematical prerequisite. When non-mathematicians explore Bat County in a concrete, physical way, we hope this leads them to both recognize, and make sense of, its many complexities and properties – many of which are not obvious on first glance.
A 21’ sculpture of meticulously arranged baseball bats is, we trust, spectacular enough to invite closer inspection, which is exactly what is desired. As participants explore the piece, the view changes in dramatic and unexpected ways: one remarkable feature of a Sierpinski Tetrahedron is just how different it appears from different points of view.
For example, from the outside on the ground, Bat Country looks like a triangle with a complex lattice of interior edges. From six specific perspective points, though, the bats align perfectly, and it appears to be a two-dimensional Sierpinski Triangle.
Fittingly enough for a baseball-themed realization, when viewed perpendicularly from the midpoint of any outside edge, the internal structure resolves into a diamond. The third-generation diamond is, alas, only visible from a perspective well off the ground, but earth-bound viewers can see the second-generation diamonds as they walk towards one of the three corners on the ground… or when looking up, from an edge.
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[edit] Materials, Illumination & Finishes
To make Bat Country visible at night (and provide an aesthetically-pleasing highlighting of its structure) each softball at each vertex will be back-lit by two high-brightness LEDs.
The Bats will be painted red and blue, with the softballs providing white highlights. Exposed steel will be galvanized.
The primary construction materials of Batcountry are:
- 384 Aluminum Softball Bats (red and blue)
- 384 B7 Alloy Steel Threaded Rod 1/2"-13 Thread, 3' Length
- 768 Hex Thick (Heavy) Nut 1/2"-13
- 768 Zinc-Plated Steel Spring Lock Washer 1/2"
- 768 Plain Steel Weld Nut 1/2"-13
- 256 custom 1/4" A36 sheet metal end caps
- 64 custom 1/4" A36 sheet metal joining plates
- 1024 Carriage Screw Zinc-Plated Steel, 1/4"-20 Thread, 1" Length
- 1024 Spring Lock Washer 1/4" Screw Size
- 1024 Steel Hex Nut 1/4"-20 Screw Size, 7/16" Width, 7/32" Height
- 130 12 Inch Softballs
- 130 Steel Coupling Nut 1/2"-13 Screw Size, 4" Length
[edit] Construction Details and Safety
Click here for Construction updates and photos ...
We intend participants to climb on the structure. Safety is the number one issue. Bat Country is designed with a 2X safety factor with a loading assumption 500lbs per horizontal bat.
The following engineering drawings show the construction of the bats and the joining plates. Each of the 64 tetrahedra will be assembled before shipment to the desert. In the desert, these will be bolted together to form the full structure. The stability of the bats and joints are the primary area of engineering. The joints needed to be strong yet also allow for easy in-field assembly. The aluminum bats themselves would not provide the axial stability from buckling so they are reinforced with 1/2" steel rods.
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Initial modeling has shown the design to be quite robust. Stress/strain analysis will be added here when available.
[edit] Playa Timeline
[edit] Pre-Event
| Friday August 22nd | ||
| 9:00 AM | Travel to Playa | |
| 7:00 PM | arrive at Playa | |
| unpack personal camp | ||
| Saturday August 23rd | ||
| 9:00 AM | check in with Artery - Fill out forms | |
| 11:00 AM | move truck to site | |
| stake and layout outline | ||
| bury batteries | ||
| 12:00 PM | unload 64 tetrahedrons | |
| assemble 16 generation 1 tetrahedrons | ||
| assemble 4 generation 2 tetrahedrons | ||
| go through site and remove all MOOP |
[edit] During Event (Daily)
| Monday 25th - Sunday 31st | |||
| 10:00AM | Check structural integrity and inspect every bolt | ||
| MOOP patrol | |||
| Check battery levels | |||
[edit] Post-Event Cleanup & Strike Plan
| Sunday August 31 | |||
| Evening | Go through site and remove all MOOP. | ||
| Ensure truck is cleaned up and ready to move. | |||
| Monday September 1 | |||
| 8:00 AM | Pack and load personal camp | ||
| 9:00 AM | Move truck into place | ||
| Remove lighting wiring ties between tetrahedrons | |||
| Install top eyelet and unbolt top tetrahedron | |||
| Unearth batteries - repair playa | |||
| 10:00 AM | Coordinate with DPW for lifting top section of tetrahedron | ||
| 10:30 AM | Break down remaining tetrahedrons down to 64 individuals | ||
| 2:00 PM | Stack tetrahedrons in 8 stacks of 8 each inside truck | ||
| Secure for transportation | |||
| 3:00 PM | Final sweep for MOOP | ||
| 3:30 PM | Site Cleared | ||
| Checkout with Artery |
[edit] The fate of Bat Country after Burning Man
Given the effort and cost involved in creating the work, it is hoped that the piece will have opportunity to appear in public in whole or in part.
In addition to the obvious path of returning the piece to Black Rock in future years, we hope that there might be an opportunity to install the piece publically in the Bay Area. Ultimately, the four second-generation component tetrahedrons, each 10’ high, might be installed in permanent locations such as playgrounds, stadiums, or other public places. While ideally we love for the sculpture or its parts to be scalable as jungle gyms wherever they land, it is likely that safety would require their installation as purely aesthetic objects.
[edit] Special Thanks
We would like to thank the following people for their generous help so far in the project:
- Aaron Ximm
- Bob Toleno
- Stella Lawless
- Andrew Hessel
- Kevin Wells
- Dan Zulevic (C&H Specialists - sheet metal fab)
- Richard Lopez (C&H Specialists - sheet metal fab)
- Hank Bombino (Rainbow Electronics - fasteners)
- Glenn Compton (Hawk Ridge Systems)
- Marty Kenney
- Juli Chamberlin
- Thomas Boutte
- Jennifer and Chris Taylor
- Mark Blackwood
- Tammy and Evan Palmer
- Beth and Greg Whitehead
- Claire and Mike Carroll
- Patrick Tidaback
- Greg Johnson
All images, designs, and text on this site © 2005-2008 Gwen Fisher and/or Paul Brown. Permission required for any capture or reuse.
