add push mechanic

The push mechanic is heavily inspired by `Into the Breach`.
Pushing a permanent moves it involuntarily in a straight line.
On collisions units receive damage and permenents pushed onto free but
unavailable tiles are destroyed.

1 files changed, 22 insertions, 5 deletions

diff --git a/rules/en/rules.md b/rules/en/rules.md
index 150435a1..feb752a7 100644
--- a/rules/en/rules.md
+++ b/rules/en/rules.md
@@ -222,11 +222,15 @@ While you control an untapped card on the board or have a playable card in hand
 
 * **Ranges** define a sphere of **tiles**
 * **Ranges** have a origin
-* **Ranges** have a radius r
-* **Ranges** with the radius r include all **tiles** which are reachable with r steps from the origin, counting each second diagonal step twice
+* **Ranges** have a radius `r`
+* **Ranges** with the radius `r` include all **tiles** which are reachable with `r` **steps** from the origin, counting each second diagonal **step** twice
 * More precisely: a **tile** (x, y), where x and y are relative to the its origin (0, 0), is in the **range** r iff $$x > y$$ and $$abs(x) + floor(abs(y) / 2)$$ else $$abs(y) + floor(abs(x) / 2)$$.
 * *Adjacent* is a common Abbreviation for "in **range** 1"
 
+## Step
+
+* A **step** is performed by placing a **permanent** from its current **tile** onto an *adjacent*
+
 # Permanents
 
 * **Permanents** are game pieces which exclusively occupy one **tile** on the map
@@ -312,9 +316,10 @@ For each permanent in the pile
 
 ## Movement
 
-* A **unit** can move within the **range** specified by its **movement**
-* The *moved* **Unit** can make as many steps in its **movement range** as its **movement**
-* Each second diagonal step counts twice
+* A **unit** can be *moved* by using its **move action**
+* A **unit** can *move* within the **range** specified by its **movement**
+* The *moved* **Unit** can make at most m **steps** where m is equal to its **movement**
+* Each second diagonal **step** counts twice
 
 ## Effects Of Units
 
@@ -359,6 +364,18 @@ Additional States a **Unit** is in are represented by putting appropriate State
 * When a *warded* **Unit** is dealt damage prevent that damage and remove that much **Ward** marks from it.
 * Damage is always prevented completely independent how many **Ward** marks are on the *warded* **Unit**
 
+# Push [X]
+
+* `X` can be neglected if it is 1
+* To *push* a **permanent** *move* it `X` **steps** in a straight line
+* **Permanents** may be *pushed* as effect of an **action** or **combat**
+* *Pushing* a **permanent** always requires a **tile** where the **push** originates
+  * When a **unit** *pushes* a **permanent** the originating **tile** is the current **tile** of the *pushing* **unit**
+* Each step must be in a straight line determined by the originating **tile** and the current **tile**
+* If a **permenent** would be *pushed* onto a *not free* **tile** it is not *pushed* further
+ * A **Unit** colliding in this way is dealt 1 **damage** by the other **permenent**
+* If a **permenent** would be *pushed* onto a *free* but not *available* **tile** destroy the **permanent**
+
 # Combat
 
 * Is initialized with an **Unit's** **attack action** or an effect