Platonic Mastery

http://halfmeme.com/threeforged.html

Platonic Mastery is a system based around the relationship between the platonic solids and the elements described in Plato’s Timaeus dialogue. It describes a world where individuals can mystically manipulate the elements and is partially inspired by the Avatar series.
https://en.wikipedia.org/wiki/Timaeus_%28dialogue%29#The_Elements

In Platonic Mastery each element has a dice size associated with it.

FIRE	EARTH	AIR	SELF	WATER	
d4	d6	d8	d12	d20	

MAKING A CHARACTER
First think about what kind of character you want to portray and write three Callings and three Traits for them.

Each Calling should be two sentences in the form “‘What I think’ and ‘What I’m going to do about it’”. 
Each time you do something BECAUSE of the “What I Think” section of a Calling, you gain one XP. 
When you complete the action described in the “What I’m going to do about it” section of a Calling you gain five experience and replace that Calling with a new one.

Each Trait should be a simple but specific word or phrase telling what makes your character stand out from the crowd.
These Traits can be invoked by you to gain Situational Dice on your roll or by the GM to add to the Obstacle Count for a roll. At the end of each session the other players must vote which Trait least described your character that session and what to replace it with, adjust your character accordingly.

Once you have Callings and Traits give your character any combination of 5 dice. You may, at any time, purchase another dice by spending XP equal to the number of your dice.

When you create your character and each time you purchase a dice you may roll all your dice. The total of this roll is your new Max Hitpoints if it is more than your previous Max Hitpoints.

PLAYING THE GAME
In Platonic Mastery each of your character's die is either live or dead. Each die starts live but when they're rolled they risk becoming dead and unusable through strain until your character sleeps.

When you attempt to achieve something non-trivial in game you bend yourself and the elements around you. The GM will tell you what action you are making and how many obstacles are making it difficult such as the situation around you, the difficulty of the task or your Traits.

You may roll as many of your live dice as you wish but you may never use all of your live dice of any single kind on a roll unless they are of the same element as the action being performed.

You can invoke your Traits and the situation around you by explaining how they make your task easier. Each invocation adds a d10 Situational Die to your roll. 

The Obstacle Count is subtracted from the result of each die rolled for all rolls except those to Make Something Break or Bleed, where it is added to the roll. This affects whether dice become dead as described in the Action.

If all the dice in a roll end up dead the action being attempted fails.

If at any point you have no live dice your character immediately falls unconscious until you have at least one live dice again.

When you take damage that is not completely avoided or absorbed the amount of remaining damage is subtracted from your hitpoints.

If at any point your character has zero or fewer hitpoints they die.

For every hour your character sleeps they regain one hitpoint and resurrect one die from dead to live.

Actions:

Make Something Break or Bleed (Fire, d4): Dice that roll four or more become dead. For each result less than four deal 10 damage to the target. 

Construct or Protect (Earth, d6): Dice that roll three or less become dead. If the roll does not fail, any structure constructed can absorb damage equal to the total of the dice roll.

Nimbly Avoid Danger (Air, d8): Dice that roll three or less become dead. If the total of the dice rolled is larger than any damage being avoided then you do not take that damage.

Restore or Heal (Water, d20): Dice that roll three or less  become dead. If the roll does not fail, damage equal to the total of the dice rolled can be healed. Dice rolled for restoration and healing always die after the roll regardless of success or failure.

Use Your Words (Self, d12): Dice that roll one or less become dead. If your roll does not fail those listening to you who you are trying to influence must roll at least one of their Self dice where rolls of 1 are dead dice. If the total of the listener’s roll is less than yours then they mark XP if their mind is changed.

Use Tools (Self, d12): Dice that roll one or less become dead. If the total of the dice rolled is greater than half your hitpoints you are successful in your attempted task.

Look With Your Eyes, Listen With Your Ears or Think with Your Brain (Self, d12): Dice that roll one or less become dead. If the dice rolled is greater than half your hitpoints you see, hear or know the thing in question.

Bend The Elements (Fire, d4 OR Earth, d6 OR Air, d8 OR Water, d20): Dice that roll two or less become dead. If the total of the dice rolled is greater than half your hitpoints you magically bend, shape or move a cubic foot of the element you are bending. It is possible to bend impure elements (metal is impure earth, blood is impure water, lava is impure fire) but the impurity counts as two obstacles. Each time you increase the size of a bend by up to a factor of five the obstacle count increases.
BEING THE GM

Play is a conversation between the players and GM. You describe the situation, they say what they want to do and roll if necessary and you describe what happens.

The GM’s responsibilities are to challenge the player characters and their beliefs with a world filled with fantastic scenes, fascinating characters and perilous dangers.

If you need stats for stuff, choose tags for your person, place or thing and give it the associated elemental dice for those tags. Then roll hitpoints for it as player characters do. You may choose tags multiple times.

Example Tags:

Fire	Earth	Air	Self	Water	
Glass Cannon
Motorized
Demonic	Man Made
Digging
Mineral
	Fast
Flying
Cowardly	Strong
Large
Brave	Undead
Swimming
Fat