Borderline Science, Inc. - Chronospatial Traversal

[Fringe Pioneer]

Chronospatial traversal is the combination of backward time travel and "instantaneous" space teleportation. Scientists, physicists, and engineers at Borderline Science, with the help of CAReFUL, have successfully created a device that can create two portals at a time for traversing anywhere in space with surfaces conductive to portals and backwards in time. They discovered that only two portals from a given Borderline Science Portable Chronospatial Traversal Tool could exist simultaneously, while other properties are similar to standard spatial portals. Also, unlike standard spatial portals, there is no need to make a distinction between portals (as would be represented by a switch on a gun) because the moment in time that you shoot a portal makes the distinction. You simply shoot a portal at one moment, then shoot another portal at another moment, then shooting a third portal would "erase" the first portal. They also discovered that Aperture Science Material Emancipation Grills worked to rid of chronospatial portals, too.

The concept is very confusing, but CAReFUL devised a simple example puzzle that utilizes chronospatial traversal to solve.

Imagine a long rectangular room divided into four spaces. Three blaster doors divide the four spaces. Up against each door on the "entry" side is a button. A door stays open only while its corresponding button is pressed down. The objective, naturally, is to exit the chamber and continue doing Science.

+                                        +
|                                        |
|                                        |
|                                        |
|                                        |
|--------------------2-------------------|
|                                       o|
|                                        |
|                                        |
|                                        |
|--------------------1-------------------|
|                                       o|
|                                        |
|                                        |
|                                        |
|--------------------0-------------------|
|                                       o|
|                                        |
|                                        |
|                    x                   |
+                                        +

CAReFUL gives the following table of example actions to take in order to escape.

Time since Start	[cs=4] "Your" Instructions
0:00	Start at beginning. Go to button.	You were never in this timeline.	[rs=2] You were never in this timeline.	[rs=3] You were never in this timeline.
0:05	Stand on button. Shoot portal in front of Door 0.	Appear in front of Door 0. Go to next button.
0:10	Shoot portal next to button and go through it.	Stand on button. Shoot portal in front of Door 1.	Appear in front of Door 1. Go to next button.
0:15	[rs=2]You are not in this timeline anymore.	Shoot portal next to button and go through it.	Stand on button. Shoot portal in front of Door 2.	Appear in front of Door 2. Exit the room.
0:20	You are not in this timeline anymore.	Shoot portal next to button and go through it.	You are free! Congratulations!

The durations may not necessarily be increments of 5 seconds, depending on how long it takes to get from one part to another, but timing is crucial. To prevent oneself from prematurely ending the recursive portal use, every odd portal (other than the first one fired after going through a Material Emancipation Grill) must be fired when or after you see yourself successfully "use" your previous portals: only then is the timeline safe and you may continue on. Despite the likely results of prematurely collapsing chronospatial recursion, we did not test the theories. CAReFUL has scheduled for some fringe pioneers to do so in a controlled manner.

[Qwerty]

My brain. It is hurting.

What if I fire one next to me, fire another next to me, and shoot myself through the portal before I can place the second? Paradox?

[Fringe Pioneer]

Essentially, if I place a portal on a wall on April 27, 20:00, wait for ten minutes doing whatever, place a new portal on the opposite wall on April 27, 20:10, and then go through that second portal, I will end up by the first portal (just like in the game Portal) and it will be April 27, 20:00 again. I will be able to spend the next ten minutes watching myself do whatever it was I was doing, until I watch myself go through the portal on April 27, 20:10. After that, I will be alone again.

Take note of the implication that, after I place the first portal and before I place the second portal, I should notice that someone (myself) is watching me until I go through the portal.

[Qwerty]

Take that. Now say I shoot myself after I enter the second portal and stand around watching myself in the first one, and before the first me makes the second portal.

[Fringe Pioneer]

CAReFUL hasn't put the fringe pioneers through that experiment yet, but there are three theories.

• There are an infinite number of timelines with no "first" or "last" timeline. Let's say "you" correspond with timeline T. The moment you create the first portal, someone from timeline S comes from the portal and watches you until you create and go through the second portal. "You" from timeline T appear in timeline U, and you kill your timeline U counterpart before he can create the second portal. There is no obvious violation.
  
  
• There is only one timeline. The universe turns out to be predetermined, and what you propose won't happen for whatever sorry excuse the universe imagines (e.g. you would be too scared to shoot yourself, or your gun jams, or you miss, or something like that). The violation, although "possible" in thought experiment, is "impossible" in reality.
  
  
• There is only one timeline. You do manage to kill yourself. The universe cycles between you killing yourself and you not killing yourself ad nauseum or until it collapses and brings everything in it into nonexistence, or else it does something unimaginable.

[monokr0me]

GV, you need to make a game, probably 2D as 3D isn't very feasible in Java, using these mechanics.