Added cliffs as separate block

core/src/mindustry/world/Tile.java

@@ -123,7 +123,7 @@ public class Tile implements Position{
     }
 
     public boolean isDarkened(){
-        return block().solid && !block().synthetic() && block().fillsTile;
+        return block.solid && !block.synthetic() && block.fillsTile;
     }
 
     public @NonNull Floor floor(){

core/src/mindustry/world/blocks/Cliff.java

@@ -0,0 +1,31 @@
+package mindustry.world.blocks;
+
+import arc.graphics.g2d.*;
+import arc.util.*;
+import mindustry.graphics.*;
+import mindustry.world.*;
+
+public class Cliff extends Block{
+
+    public Cliff(String name){
+        super(name);
+        breakable = alwaysReplace = false;
+        solid = true;
+        cacheLayer = CacheLayer.walls;
+        fillsTile = false;
+        hasShadow = false;
+    }
+
+    @Override
+    public void draw(Tile tile){
+        int r = tile.rotation();
+        for(int i = 0; i < 4; i++){
+            if((r & (1 << i)) != 0){
+                Draw.color(Tmp.c1.set(tile.floor().color).mul(1.3f + (i >= 2 ? -0.4f : 0.3f)));
+                Draw.rect(region, tile.worldx(), tile.worldy(), i * 90f);
+            }
+        }
+
+        Draw.color();
+    }
+}