diff --git a/script.js b/script.js
index 9de35ac..cab1ce5 100644
--- a/script.js
+++ b/script.js
@@ -264,15 +264,15 @@ class Board {
     orb.dataset.symbol = symbol;
     this.$orbs.appendChild(orb);
 
-    orb.addEventListener('click', () => {
-      this.onOrbClick(arrayIndex, orb);
-    });
-
     let object = {
       node: orb,
       symbol
     };
 
+    orb.addEventListener('click', () => {
+      this.onOrbClick(arrayIndex, object);
+    });
+
     this.grid[arrayIndex] = object;
     return object;
   }
@@ -518,6 +518,8 @@ class Board {
       'mercury', 'lead', 'tin', 'iron', 'copper', 'silver', 'gold'
     ];
 
+    this.metalSequence = ['lead', 'tin', 'iron', 'copper', 'silver', 'gold'];
+
     this.orbColors = {
       salt: '#f2e7b4',
       air: '#9ee0ff',
@@ -717,7 +719,7 @@ class Game {
   /**
    * Get a random and randomly flipped template
    *
-   * @return Number[]
+   * @return Number[] - template indices; this is a clone, free to modify
    */
   getRandomTemplate() {
     let names = Object.keys(this.layoutTemplates);
@@ -842,10 +844,16 @@ class Game {
     this.board.removeAllOrbs();
 
     let allowed = [];
+    let outsideTemplate = [];
     for (let i = 0; i <= 120; i++) {
       let allo = template.includes(i);
       allowed.push(allo);
 
+      let { x, y } = this.board.gridIndexToXy(i);
+      if (!allo && !this.isOutside(x, y)) {
+        outsideTemplate.push(i);
+      }
+
       // Highlight pattern shape
 
       // if (this.board.tiles[i]) {
@@ -883,9 +891,23 @@ class Game {
     };
 
     const findAvailableIndex = () => {
-      for (let i = 6; i >= 0; i--) {
-        const n = findAvailableIndexWithNeighbours(i);
-        if (n !== false) return n;
+      for (let j = 0; j < 2; j++) {
+        for (let i = 6; i >= 0; i--) {
+          const n = findAvailableIndexWithNeighbours(i);
+          if (n !== false) return n;
+        }
+
+        // this corrupts the template, but makes the likelihood of quickly finding a valid solution much higher.
+        if (template.length !== 121) {
+          console.warn("Adding extra tile to template");
+          while (1) {
+            let toAdd = outsideTemplate[this.rng.nextInt(outsideTemplate.length)];
+            if (allowed.includes(toAdd)) continue;
+            allowed[toAdd] = true;
+            template.push(toAdd);
+            break;
+          }
+        }
       }
 
       throw Error("Failed to find available tile");
@@ -895,20 +917,33 @@ class Game {
 
     const toPlace = this.buildPlacementList();
 
-    // unpack the pairs
-    let toPlace_stack = toPlace.reduce((a, c) => {
-      a.push(c[0]);
-      a.push(c[1]);
-      return a;
-    }, []);
+    let solution = [];
+    while (toPlace.length > 0) {
+      let symbol1 = toPlace.pop();
+      let index1 = findAvailableIndex();
+      place(index1, symbol1);
+
+      let symbol2 = toPlace.pop();
+      let index2 = findAvailableIndex();
+      place(index2, symbol2);
 
-    while (toPlace_stack.length > 0) {
-      place(findAvailableIndex(), toPlace_stack.pop())
+      if (!this.isAvailable(index1)) {
+        throw new Error("Solution contains a deadlock.");
+      }
+
+      let p;
+      p = this.board.gridIndexToXy(index1);
+      solution.push([symbol1, `${p.x}×${p.y}`, index1]);
+
+      p = this.board.gridIndexToXy(index1);
+      solution.push([symbol1, `${p.x}×${p.y}`, index1]);
     }
 
+    solution.reverse();
+
     console.info("Found a valid board!");
 
-    console.log('Solution: ', toPlace);
+    console.log('Solution: ', solution);
   }
 
   shuffleArray(a) {
@@ -1000,9 +1035,16 @@ class Game {
       toPlace.splice(mPos[i] + i, 0, pair);
     });
 
-    return toPlace;
+    return toPlace.reduce((a, c) => {
+      a.push(c[0]);
+      a.push(c[1]);
+      return a;
+    }, []);
   }
 
+  /**
+   * Convert the strings in the board array to actual SVG orbs (strings are a placeholder to speed up board solving)
+   */
   renderPreparedBoard() {
     for (let n = 0; n <= 120; n++) {
       if (this.board.grid[n] !== null) {
@@ -1013,10 +1055,74 @@ class Game {
     }
   }
 
+  /**
+   * Update orb availability status (includes effects)
+   */
   updateOrbDisabledStatus() {
     for (let n = 0; n <= 120; n++) {
       if (this.board.grid[n]) {
-        this.board.grid[n].node.classList.toggle('disabled', !this.isAvailable(n));
+        const ava = this.isAvailableAdvanced(n);
+        this.board.grid[n].node.classList.toggle('disabled', !ava);
+      }
+    }
+  }
+
+  isAvailableAdvanced(n) {
+    let ava = this.isAvailable(n);
+
+    const sym = this.board.grid[n].symbol;
+    if (this.board.metalSequence.includes(sym)) {
+      if (sym !== this.nextMetal) {
+        ava = false;
+      }
+    }
+
+    return ava;
+  }
+
+  /**
+   * Handle orb click
+   * @param n
+   * @param orb
+   */
+  ingameBoardClick(n, orb) {
+    if (this.isAvailableAdvanced(n)) {
+      if (orb.symbol === 'gold') {
+        this.board.removeOrbByIndex(n);
+        this.selectedOrb = null;
+
+        if (this.countOrbs() === 0) {
+          console.info("Good work!");
+        }
+        return;
+      }
+
+      if (this.selectedOrb === null) {
+        this.selectedOrb = { n, orb };
+        orb.node.classList.add('selected');
+      }
+      else {
+        if (this.selectedOrb.n === n) {
+          orb.node.classList.remove('selected');
+          this.selectedOrb = null;
+        }
+        else {
+          const otherSymbol = this.selectedOrb.orb.symbol;
+
+          if (this.getPairSymbols(orb.symbol).includes(otherSymbol)) {
+            // paired
+            this.board.removeOrbByIndex(n);
+            this.board.removeOrbByIndex(this.selectedOrb.n);
+
+            if ([orb.symbol, otherSymbol].includes(this.nextMetal)) {
+              this.advanceMetal();
+            }
+
+            this.selectedOrb = null;
+          }
+
+          this.updateOrbDisabledStatus();
+        }
       }
     }
   }
@@ -1026,8 +1132,13 @@ class Game {
     //   console.log(n, this.board.gridIndexToXy(n));
     // };
 
-    const RETRY_IN_TEMPLATE = 100;
-    const RETRY_NEW_TEMPLATE = 15;
+    this.selectedOrb = null;
+
+    let self = this;
+    this.board.onOrbClick = (n, orb) => self.ingameBoardClick(n, orb);
+
+    const RETRY_IN_TEMPLATE = 50;
+    const RETRY_NEW_TEMPLATE = 50;
 
     // retry loop, should not be needed if everything is correct
     let suc = false;
@@ -1052,19 +1163,50 @@ class Game {
       }
     }
 
-    if (!suc) {
-      // show the failed attempt
-      this.renderPreparedBoard();
-      this.updateOrbDisabledStatus();
+    this.nextMetal = 'lead';
+    this.renderPreparedBoard();
+    this.updateOrbDisabledStatus();
 
+    if (!suc) {
       alert(`Sorry, could not find a valid board setup after ${numretries} retries.`);
-      return;
     } else {
       console.info(`Found valid solution (with ${numretries} retries)`);
     }
+  }
 
-    this.renderPreparedBoard();
-    this.updateOrbDisabledStatus()
+  getPairSymbols(first) {
+    return {
+      'salt': ['salt', 'air', 'fire', 'water', 'earth'],
+      'air': ['salt', 'air'],
+      'fire': ['salt', 'fire'],
+      'water': ['salt', 'water'],
+      'earth': ['salt', 'earth'],
+      'mercury': [this.nextMetal],
+      'lead': ['mercury'],
+      'tin': ['mercury'],
+      'iron': ['mercury'],
+      'copper': ['mercury'],
+      'silver': ['mercury'],
+      'gold': [],
+      'mors': ['vitae'],
+      'vitae': ['mors'],
+    }[first];
+  }
+
+  advanceMetal() {
+    this.nextMetal = this.board.metalSequence[this.board.metalSequence.indexOf(this.nextMetal) + 1];
+    console.debug(`Next metal unlocked: ${this.nextMetal}`);
+  }
+
+  countOrbs() {
+    let n = 0;
+    // todo use reduce
+    this.board.grid.forEach((x) => {
+      if (x !== null) {
+        n++;
+      }
+    });
+    return n;
   }
 }