diff --git a/mods/CsC.js b/mods/CsC.js
new file mode 100644
index 00000000..4b1a36f9
--- /dev/null
+++ b/mods/CsC.js
@@ -0,0 +1,138 @@
+runAfterLoad(function(){
+  const patternCache = {};
+  let currentPatternID = null;
+  let nextPatternID = 1;
+  const undoStack = [];
+  const redoStack = [];
+  const maxHistory = 50;
+
+  function saveAction(pixels){
+    undoStack.push(pixels.map(px=>({x:px.x,y:px.y,element:px.element,color:px.color,patternID:px.patternID})));
+    if(undoStack.length>maxHistory) undoStack.shift();
+    redoStack.length=0;
+  }
+
+  function undo(){
+    if(!undoStack.length) return;
+    const action = undoStack.pop();
+    const redoPixels = [];
+    action.forEach(a=>{
+      const px = pixelMap[a.x][a.y];
+      redoPixels.push({x:a.x,y:a.y,element:px.element,color:px.color,patternID:px.patternID});
+      px.element=a.element; px.color=a.color; px.patternID=a.patternID;
+    });
+    redoStack.push(redoPixels);
+  }
+
+  function redo(){
+    if(!redoStack.length) return;
+    const action = redoStack.pop();
+    const undoPixels = [];
+    action.forEach(a=>{
+      const px = pixelMap[a.x][a.y];
+      undoPixels.push({x:a.x,y:a.y,element:px.element,color:px.color,patternID:px.patternID});
+      px.element=a.element; px.color=a.color; px.patternID=a.patternID;
+    });
+    undoStack.push(undoPixels);
+  }
+
+  elements.undo_tool = {
+    color:"#f00", tool:undo, category:"tools", description:"Undo last action"
+  };
+  elements.redo_tool = {
+    color:"#0f0", tool:redo, category:"tools", description:"Redo last undone action"
+  };
+
+  elements.pattern_painter = {
+    color:"#888", tool:function(pixel,x,y){
+      if(!currentPatternID){
+        currentPatternID="pattern_"+(nextPatternID++);
+        patternCache[currentPatternID]=Array(8).fill().map(()=>Array(8).fill(0));
+      }
+      const pat = patternCache[currentPatternID];
+      const mx=Math.floor((x*8)%8), my=Math.floor((y*8)%8);
+      pat[my][mx]=1-pat[my][mx];
+    }, category:"tools", description:"Pattern painter (8x8)"
+  };
+
+  function drawPattern(ctx, pat, dx, dy, s){
+    for(let py=0;py<8;py++)for(let px=0;px<8;px++){
+      if(pat[py][px]){
+        ctx.fillStyle="#444";
+        ctx.fillRect(dx+px*s/8, dy+py*s/8, s/8, s/8);
+      }
+    }
+  }
+
+  elements.decor_block={
+    color:"#fff", behavior:behaviors.WALL, category:"solids",
+    onPlace:p=>{if(currentPatternID)p.patternID=currentPatternID; saveAction([p]);},
+    renderer:function(p,ctx,dx,dy,s){
+      if(p.patternID) drawPattern(ctx, patternCache[p.patternID], dx, dy, s);
+      else { ctx.fillStyle=p.color; ctx.fillRect(dx,dy,s,s); }
+    }
+  };
+
+  elements.batch_filler={
+    color:"#66f",
+    tool:function(pixel){
+      const area=[];
+      for(let dx=-2;dx<=2;dx++)for(let dy=-2;dy<=2;dy++){
+        const px=pixelMap[pixel.x+dx]?.[pixel.y+dy];
+        if(px){px.element="decor_block"; if(currentPatternID) px.patternID=currentPatternID; area.push(px);}
+      }
+      saveAction(area);
+    },
+    category:"tools",
+    description:"Fill 5x5 area with pattern"
+  };
+
+  elements.stamp_tool={
+    color:"#ff0",
+    tool:function(pixel){
+      if(!currentPatternID) return;
+      const area=[];
+      for(let dx=0;dx<8;dx++)for(let dy=0;dy<8;dy++){
+        const px=pixelMap[pixel.x+dx]?.[pixel.y+dy];
+        if(px){px.element="decor_block"; px.patternID=currentPatternID; area.push(px);}
+      }
+      saveAction(area);
+    },
+    category:"tools",
+    description:"Stamp 8x8 pattern"
+  };
+
+  elements.gradient_tool={
+    color:"#0ff",
+    tool:function(pixel){
+      const area=[];
+      for(let dx=0;dx<5;dx++)for(let dy=0;dy<5;dy++){
+        const px=pixelMap[pixel.x+dx]?.[pixel.y+dy];
+        if(px){
+          const r=Math.floor(255*dx/4), b=Math.floor(255*dy/4);
+          px.element="decor_block";
+          px.color=`rgb(${r},0,${b})`;
+          area.push(px);
+        }
+      }
+      saveAction(area);
+    },
+    category:"tools",
+    description:"Paint 5x5 gradient"
+  };
+
+  elements.curve_tool={
+    color:"#f0f",
+    tool:function(pixel){
+      const area=[];
+      for(let i=0;i<5;i++){
+        const px=pixelMap[pixel.x+i]?.[pixel.y+Math.floor(Math.sin(i/4*Math.PI)*4)];
+        if(px){px.element="decor_block"; if(currentPatternID) px.patternID=currentPatternID; area.push(px);}
+      }
+      saveAction(area);
+    },
+    category:"tools",
+    description:"Draw sine curve with pattern"
+  };
+
+});
diff --git a/mods/Decor.js b/mods/Decor.js
new file mode 100644
index 00000000..cf15ecaf
--- /dev/null
+++ b/mods/Decor.js
@@ -0,0 +1,100 @@
+runAfterLoad(function(){
+  const patternCache = {};
+  let currentPatternID = null;
+  let nextPatternID = 1;
+
+  elements.pattern_painter = {
+    color:"#888", tool:function(pixel,x,y){
+      if(!currentPatternID){
+        currentPatternID = "pattern_"+(nextPatternID++);
+        patternCache[currentPatternID] = Array(8).fill().map(()=>Array(8).fill(0));
+      }
+      const pat = patternCache[currentPatternID];
+      const mx = Math.floor((x*8)%8), my = Math.floor((y*8)%8);
+      pat[my][mx] = 1 - pat[my][mx];
+    },
+    category:"tools",
+    description:"Pattern painter (8x8)"
+  };
+
+  function drawPattern(ctx, pat, dx, dy, s){
+    for(let py=0;py<8;py++){
+      for(let px=0;px<8;px++){
+        if(pat[py][px]){
+          ctx.fillStyle = "#444";
+          ctx.fillRect(dx + px*s/8, dy + py*s/8, s/8, s/8);
+        }
+      }
+    }
+  }
+
+  function blendColors(c1,c2,t){
+    const parse = c=>parseInt(c.slice(1),16);
+    const r1=((parse(c1)>>16)&255), g1=((parse(c1)>>8)&255), b1=(parse(c1)&255);
+    const r2=((parse(c2)>>16)&255), g2=((parse(c2)>>8)&255), b2=(parse(c2)&255);
+    const r=Math.floor(r1*(1-t)+r2*t), g=Math.floor(g1*(1-t)+g2*t), b=Math.floor(b1*(1-t)+b2*t);
+    return "#"+((1<<24)+(r<<16)+(g<<8)+b).toString(16).slice(1);
+  }
+
+  elements.decor_block = {
+    color:"#fff", behavior:behaviors.WALL, category:"solids",
+    onPlace: p=>{ if(currentPatternID) p.patternID=currentPatternID; },
+    renderer: function(p, ctx, dx, dy, s){
+      if(p.patternID){
+        drawPattern(ctx, patternCache[p.patternID], dx, dy, s);
+      } else { ctx.fillStyle=p.color; ctx.fillRect(dx, dy, s, s); }
+    }
+  };
+
+  elements.fader_block = {
+    color:"#fff", behavior:behaviors.WALL, category:"solids",
+    onPlace: p=>{ if(currentPatternID) p.patternID=currentPatternID; },
+    renderer: function(p, ctx, dx, dy, s){
+      const pat = p.patternID ? patternCache[p.patternID] : null;
+      if(!pat){ ctx.fillStyle=p.color; ctx.fillRect(dx, dy, s, s); return; }
+      for(let py=0;py<8;py++){
+        const t = py/7;
+        for(let px=0;px<8;px++){
+          const c = pat[py][px] ? blendColors("#000","#555",t) : blendColors("#ccc","#eee",t);
+          ctx.fillStyle=c;
+          ctx.fillRect(dx+px*s/8, dy+py*s/8, s/8, s/8);
+        }
+      }
+    }
+  };
+
+  elements.cloth = {
+    color:"#aaa", behavior:behaviors.POWDER, category:"solids",
+    onPlace: p=>{ if(currentPatternID) p.patternID=currentPatternID; p.vy=0; },
+    tick: function(p){
+      if(p.y+1>=pixelGridHeight) return;
+      const below = pixelMap[p.x][p.y+1];
+      if(!below||elements[below.element].behavior!==behaviors.WALL) p.y++;
+    },
+    renderer: function(p, ctx, dx, dy, s){
+      if(p.patternID) drawPattern(ctx, patternCache[p.patternID], dx, dy, s);
+      else ctx.fillStyle=p.color; ctx.fillRect(dx, dy, s, s);
+    }
+  };
+
+  elements.fence_block = {
+    color:"#666", behavior:behaviors.WALL, category:"solids",
+    onPlace: p=>{ if(currentPatternID) p.patternID=currentPatternID; },
+    renderer: function(p, ctx, dx, dy, s){
+      if(p.patternID) drawPattern(ctx, patternCache[p.patternID], dx, dy, s);
+      else ctx.fillStyle=p.color; ctx.fillRect(dx, dy, s, s);
+    }
+  };
+
+  runEveryTick(function(){
+    renderPrePixel(function(p, ctx, dx, dy, s){
+      if(p.element==="decor_block"||p.element==="fader_block"||p.element==="cloth"||p.element==="fence_block"){
+        const shade = ctx.createLinearGradient(dx, dy, dx, dy+s);
+        shade.addColorStop(0,"rgba(0,0,0,0)");
+        shade.addColorStop(1,"rgba(0,0,0,0.3)");
+        ctx.fillStyle=shade;
+        ctx.fillRect(dx, dy, s, s);
+      }
+    });
+  });
+});