Is a flawless trick die possible? Trick dice have been used in gambling and magic shows. These are dice that, when rolled, will land with a preferred number facing upwards. This makes the result of rolling the dice non-random.
I was able to find a few ways to make trick dice, and I'm sure there are many more methods.


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*Melt the dice in an oven.

*Drill and fill a hole with heavier material.


While these methods do work, they are not flawless. It's possible for the dice to still produce an unwanted result.
I was wondering with new materials like liquid metal and such things. Is it possible to create a truly flawless die, which when thrown on a flat surface will always produce the same result?
 A: I think it is possible but would require advanced electronic sensors and some kind of moterized spinning system inside it. If there are no external forces, angular momentum is conserved. So if the internal mechanisms spin one way the dice will have a torque the opposing way.
A: There are at least urban myths of dies with internal chambers filled with mercury. When held in a particular way the mercury flows into a chamber opposite the desired number, making that side of the die heavier, but when held in another way the mercury flows back into the center so the die behaves essentially as normal. 
This is necessary for games where both players use the same die - otherwise there wouldn't be much point having a rigged one which came up 6 for both of you!
A: Passive flawless trick die is possible only if it has not cubic shape. That is in any position except the desired its center of mass's projection to the horizontal plane should be outside of the area which is in contact with base plane.
This is a principle of Ploy-toy doll. You can start with a spheric ploy-toy and then add some tiny "ribs".
A: Possible, as the die is not in fact an exact cube, there is a bevel on the edges. So the 'always down' face must be coated with enough Neutronium to shift the center of gravity over the edge of the bevel. 
What, no Neutronium?? Maybe use Tungsten, and the rest of the die of aerogel. 
There will be a very small chance it can land heavy side up, though. It would be stable in that position, too.
