diff --git a/src/index.html b/src/index.html
index 4018222..c0fedb6 100644
--- a/src/index.html
+++ b/src/index.html
@@ -151,7 +151,7 @@ <h3>Literals</h3>
                         <p><code data-symbol="0123456789">0123456789</code> Push the number (0-9)</p>
                     </div>
                     <div>
-                        <p><code data-symbol="abcdef">abcdef</code> Push the hexadecimal (10-15)</p>
+                        <p><code data-symbol="abcdef">abcdef</code> Push the number in hexadecimal (10-15)</p>
                     </div>
                 </div>
 
@@ -165,10 +165,7 @@ <h3>Literals</h3>
                 <p><code data-symbol=")(">)(</code> Greater than, less than. Push 1 or 0 to the stack.</p>
 
                 <p><code data-symbol="'&quot;">'" </code> Enable or disable string parsing mode. In string parsing mode
-                    all characters are
-                    pushed
-                    to the stack instead of executed.</p>
-
+                    all characters are pushed to the stack instead of executed.</p>
                 <h3>Stack</h3>
 
                 <div class="two-columns">
@@ -178,7 +175,7 @@ <h3>Stack</h3>
                     </div>
                     <div>
                         <p><code data-symbol="~">~</code> Delete the top element of the stack</p>
-                        <p><code data-symbol="@">@</code> Move the top elemnt of the stack back 2</p>
+                        <p><code data-symbol="@">@</code> Move the top element of the stack back 2</p>
                     </div>
                 </div>
 
diff --git a/src/scripts/interpreter.ts b/src/scripts/interpreter.ts
index 6a095ec..bc730f2 100644
--- a/src/scripts/interpreter.ts
+++ b/src/scripts/interpreter.ts
@@ -124,7 +124,7 @@ const commands = {
     '*': wrap((a, b) => a * b),
     '-': wrap((a, b) => b - a),
     ',': wrap((a, b) => b / a),
-    '%': wrap((a, b) => b % a),
+    '%': wrap((a, b) => ((b % a) + a) % a),
     '=': (o: ProgramState) => {
         push(o, Number(pop(o) == pop(o)))
     },
@@ -158,12 +158,16 @@ const commands = {
         push(o, x); push(o, z); push(o, y);
     },
     '{': (o: ProgramState) => {
-        let a = o.stacks[o.stacks.length - 1].contents.shift();
-        push(o, a as number);
+        if (o.stacks[o.stacks.length -1].contents.length > 0) {
+            let a = o.stacks[o.stacks.length - 1].contents.shift();
+            push(o, a as number);
+        }
     },
     '}': (o: ProgramState) => {
-        let a = o.stacks[o.stacks.length - 1].contents.pop();
-        o.stacks[o.stacks.length - 1].contents.unshift(a as number);
+        if (o.stacks[o.stacks.length -1].contents.length > 0) {
+            let a = o.stacks[o.stacks.length - 1].contents.pop();
+            o.stacks[o.stacks.length - 1].contents.unshift(a as number);
+        }
     },
     'r': (o: ProgramState) => {
         o.stacks[o.stacks.length - 1].contents.reverse();
@@ -221,6 +225,13 @@ const commands = {
     },
     'g': (o: ProgramState) => {
         let [y, x] = [pop(o), pop(o)];
+        if (x < 0) {
+            x = 0;
+        }
+        if (y < 0) {
+            y = 0;
+        }
+
         if (y < o.program.length && x < o.program[y].length) {
             push(
                 o,