In Keyword Design, I use a single word as inspiration for a mundane item, a magic item, a feat, a spell, and a class option. Today’s word is “recursion” and was suggested by Peter.

So, recursion. The repeated application of a recursive procedure. I usually look up the words that have been suggested to broaden how they can be applied; This time I had to look it up to make sure that word meant what I thought it meant.
This was the first abstract concept I was asked to design for and I thought it was a fun challenge. As usual, a keyword outside my comfort zone lead me in unexpected design directions, which is my favourite thing about writing this blog.

“Recursion”
TYPE	NAME	DESCRIPTION
Mundane Item	Weighted Coin	A trick coin designed to land in the flipper’s favour.
Magic Item	Safe Knight Tinker Toy	A magical figurine of a knight on horseback that allows a character to take their turn in a round twice and choose the prefered outcome.
Feat	Environmental Ricochet	Use your opponents cover to the advantage of your ranged attack.
Spell	Moment in Time	Target does only uses up one use of a rounds/day ability for the duration of the spell as long as they repeat the exact same action every turn.
Class Option	Proviso	A rogue archetype that can makes small sacrifices now as an investment in more benefits later.

New Mundane Items
WEIGHTED COIN
Price 15 gp (100 gp for a masterwork weighted coin); Weight –
This innocuous metal coin is almost indistinguishable from a typical coin of its mint. However, in skilled hands its flip can be controlled to land in the flipper’s favour.
A weighted coin grants a +2 circumstance bonus to Bluff checks to perform an inconspicuous action, specifically flipping the coin to land on the desired side (typically heads or tails). A masterwork weighted coin instead grants a +5 circumstance bonus to this check. If the coin is from a foreign mint -ie it is a coin from a neighbouring country- the bonus granted is doubled. A weighted coin from a foreign mint (relative to where it was purchased) costs 50% more than a domestic coin.

Not the strongest representation of the theme, but I think representative enough. The challenge of designing mundane items is justifying an ability it grants in non-magical ways.
Originally this was going to be a bonus to Sleight of Hand checks, but the closest existing mechanics to conning a game of chance is the perform an inconspicuous action use of the Bluff skill. I think it works either way. 

New Magic Item
FIGURINES OF WONDROUS POWER (SAFE KNIGHT TINKER TOY)
Aura strong abjuration; CL 13th
Slot none; Price 36 000 gp (type I); Weight 1 lb.
DESCRIPTION
Although this miniature brass statue of a knight on horseback is made up of gears, cogs, and other clockwork components, it is not a clockwork creature. The gears rest against one another rather than interconnect as a machine, fused together through alchemical means. Despite this, once per day the knight and her steed can be brought to life as a swift action to protect her owner from themselves.
Once activated, the safe knight tinker toy marches around her owner for six seconds, during which time the owner can perform their turn normally. After six seconds, the knight retraces her steps. The outcome of the owner’s actions are reversed and the owner has another six seconds to perform their turn. They can perform the same actions, different actions, or a combination of the two.
Once the safe knight tinker toy has completed her return march, the owner decides which of the two sets of actions they performed actually take effect. The results of those actions take effect immediately, and the results of the other set of actions never take effect.
CONSTRUCTION
Requirements Craft Wondrous Item, elude time; Cost 18 000 gp

I like just about everything about this. It’s flexible enough to use to figure out which switch to flip in a Mass Effect 3 stand off, or to drop a fireball twice and just take the better roll.
I like chronomancy and have used time travel as a plot point in many of my homebrew campaigns, but on a PC level, the ability to control time can be problematic. Rogue Genius Games’ Time Thief base class has a high level ability similar to what the safe knight tinker toy grants, but it can be triggered after the player takes their round. Even though “before the results are determined” is one of my pet peeves of game design, I prefer players making that decision up front in this case for logistic reasons.
I considered making this an expendable item, but I know as a player that means I would never use it, and most people I play with would rather sell an expensive consumable item than sit on it just in case. 

New Feat
ENVIRONMENTAL RICOCHET (Combat)
Your wayward projectiles bounce back towards your intended target.
Prerequisites: Point-Blank Shot, Precise Shot, base attack bonus +6.
Benefit: You can pay extra attention to your environment when making a shot, measuring how to use it to your advantage. When using the attack action to make a single ranged attack with a weapon, you gain a +1 circumstance bonus to attack and damage for every object large enough to provide your target cover or wall within 10 feet of your target. If your attack misses, you can make a second attack roll without this bonus and with a -4 penalty. Your target does not gain the benefits of cover against this second attack. This second attack deals half the damage the first attack would have on a successful hit.

I love the word ricochet. It’s fun to say and has a very visual meaning.
I like the flexibility of either using this attack as a shot with a back-up plan or taking a Hail Mary shot that is in actuality an attempt to work around cover. Bonus points if you use this feat with a boomerang.
I’m not positive a similar trick shot feat doesn’t already exist, I don’t play a lot of archers and haven’t committed the Ranged Tactics Toolbox to memory yet.  

New Spell
MOMENT IN TIME
School transmutation; Level bard 4, cleric/oracle 4, occultist 4, sorcerer/wizard 4, witch 4
Casting Time 1 standard action
Components V, S, M (sand from an hourglass)
Range touch
Target creature touched
Duration 1 round/level (D)
Saving Throw none; Spell Resistance no
As the sands used in the casting of this spell pour up and down like an hourglass aura, they guide the target of your spell to repeat their movement like clockwork.
As long as the target of the spell performs the exact same standard or full round action on the exact same target every round for the duration of the spell, they only expend one use of any ability they use that is normally limited to a certain number of uses per day, such as a barbarian’s rage or a paladin’s lay on hands ability.
Performing a different standard or full round action or targeting a different creature immediately ends the moment in time.

A tactical Groundhog Day spell, it lives in a strange space where it rewards a player for not making a decision on their turn. It strikes me as a flawed design starting point but an acceptable design end point for an option. 

New Class Option
PROVISOR (ROGUE ARCHETYPE)
They say there is no honour amongst thieves, but there is codependence. Thieves guilds need administrators who understand the immediate dangers of the rogue lifestyle and how to deal with them, but who are also farsighted enough to plan for the future.
Recurrent Sneak Attack (Ex): A provisor who can catch an opponent unable to defend himself effectively from her attack can strike a vital spot for extra damage, like a standard rogue, but she can also make note of her target’s vulnerability to use against him in the future. When a provisor is able to sneak attack an opponent, she can choose to take a penalty on all sneak attack dice she rolls against that target equal to the number of rounds she wishes to extend her sneak attack. For example, if she chooses to take a -2 penalty on all sneak attack dice rolls this turn, all of her attacks against that target for the next 2 rounds gain the benefits of sneak attack, including the -2 penalty, even if the provisor’s attacks wouldn’t normally grant sneak attack, such as if the rogue is no longer flanking their target or the target gains total concealment. She can take a penalty on recurrent sneak attacks up to her Intelligence modifier. The minimum damage each sneak attack die can deal is 1, regardless of the penalty the provisor chooses to take.
This ability alters sneak attack.
Contingency Planner (Ex): At 2nd level, a provisor plots out potential problems they expect to face that day and work out how to overcome them. This is represented by a pool of contingency points equal to the Intelligence modifier plus 1/2 their rogue level. She can use contingency points to add a +1 bonus to attack rolls, skill checks, or saving throws. She must choose to spend these contingency points before making a roll. At 4th level, she can spend contingency points to add up to a +3 bonus. At 8th level, she can spend contingency points to add up to a +5 bonus and once per day she can choose to spend contingency points after the roll is made but before the results are determined.
This ability replaces evasion, uncanny dodge, and improved uncanny dodge.

The name of an option is either the first or last step in my design process. For the provisor, I’ve been brainstorming names for it, with choices like executive and adroit on the shortlist until I realized I already had a name for this archetype in my notes that I felt was the strongest choice of all.
Again I design an archetype that alters or replaces seemingly untouchable class features and still retains the class’ feel. I like what I did here, including a last minute change to recurrent sneak attack. Originally the provisor gave up sneak attack dice to gain the benefits of  sneak attack in later rounds. That meant this was really only useful when you had 3d6 sneak attack, since there’s no advantage to turning 2d6 sneak attack in one round into 1d6 sneak attack over two rounds. Making it a -1 penalty instead means it can be used right from level 1. Also tying it to Intelligence encourages building a smarter rogue, which supports the flavour without forcing a prerequisite or the like.

Thanks again to Peter for the keyword suggestion! If you have thoughts on the balance and use of these abilities, or you would like to offer a single word that you think can inspire a mundane item, a magic item, a feat, a spell, and a class option, let me know in the comments below!