diff --git a/src/ShaderWorker.ts b/src/ShaderWorker.ts
index a7a9dd1..80c4c9e 100644
--- a/src/ShaderWorker.ts
+++ b/src/ShaderWorker.ts
@@ -185,7 +185,22 @@ class ShaderWorker {
           'midLevel',
           'trebleLevel',
           'bpm',
+          '_t',
+          'bx',
+          'by',
+          'sx',
+          'sy',
+          'qx',
+          'qy',
           `
+                    // Shader-specific helper functions
+                    const clamp = (value, min, max) => Math.min(Math.max(value, min), max);
+                    const lerp = (a, b, t) => a + (b - a) * t;
+                    const smooth = (edge, x) => { const t = Math.min(Math.max((x - edge) / (1 - edge), 0), 1); return t * t * (3 - 2 * t); };
+                    const step = (edge, x) => x < edge ? 0 : 1;
+                    const fract = (x) => x - Math.floor(x);
+                    const mix = (a, b, t) => a + (b - a) * t;
+                    
                     // Timeout protection
                     const startTime = performance.now();
                     let iterations = 0;
@@ -223,7 +238,7 @@ class ShaderWorker {
 
   private isStaticExpression(code: string): boolean {
     // Check if code contains any variables using regex for better accuracy
-    const variablePattern = /\b(x|y|t|i|r|a|u|v|c|f|d|n|b|bn|bs|be|bw|m|l|k|s|e|w|h|p|z|j|o|g|bpm|mouse[XY]|mousePressed|mouseV[XY]|mouseClickTime|touchCount|touch[01][XY]|pinchScale|pinchRotation|accel[XYZ]|gyro[XYZ]|audioLevel|bassLevel|midLevel|trebleLevel)\b/;
+    const variablePattern = /\b(x|y|t|i|r|a|u|v|c|f|d|n|b|bn|bs|be|bw|m|l|k|s|e|w|h|p|z|j|o|g|bpm|bx|by|sx|sy|qx|qy|mouse[XY]|mousePressed|mouseV[XY]|mouseClickTime|touchCount|touch[01][XY]|pinchScale|pinchRotation|accel[XYZ]|gyro[XYZ]|audioLevel|bassLevel|midLevel|trebleLevel)\b/;
 
     return !variablePattern.test(code);
   }
@@ -481,6 +496,14 @@ class ShaderWorker {
           const jitter = ((x * 73856093 + actualY * 19349663) % 256) / 255; // deterministic per-pixel random
           const oscillation = Math.sin(time * 2 * Math.PI + radius * 0.1); // wave oscillation
           const goldenRatio = 1.618033988749; // golden ratio constant
+          
+          // Calculate new spatial variables
+          const bx = x >> 4; // Block x coordinate (16-pixel blocks)
+          const by = actualY >> 4; // Block y coordinate (16-pixel blocks)
+          const sx = x - (fullWidth >> 1); // Signed x coordinate (centered at origin)
+          const sy = actualY - (fullHeight >> 1); // Signed y coordinate (centered at origin)
+          const qx = x >> 3; // Quarter block x coordinate (8-pixel blocks)
+          const qy = actualY >> 3; // Quarter block y coordinate (8-pixel blocks)
 
           const value = this.compiledFunction!(
             x,
@@ -535,7 +558,14 @@ class ShaderWorker {
             message.bassLevel || 0,
             message.midLevel || 0,
             message.trebleLevel || 0,
-            message.bpm || 120
+            message.bpm || 120,
+            (mod: number) => time % mod,
+            bx,
+            by,
+            sx,
+            sy,
+            qx,
+            qy
           );
           const safeValue = isFinite(value) ? value : 0;
           const [r, g, b] = this.calculateColor(
@@ -1113,6 +1143,9 @@ class ShaderWorker {
     processedCode = processedCode.replace(/\bSQRT1_2\b/g, 'Math.SQRT1_2');
     processedCode = processedCode.replace(/\bSQRT2\b/g, 'Math.SQRT2');
 
+    // Add custom time function t() with modulo wrapping
+    processedCode = processedCode.replace(/\bt\s*\(/g, '_t(');
+
     return processedCode;
   }
 
diff --git a/src/components/HelpPopup.tsx b/src/components/HelpPopup.tsx
index 368d44c..7fdf356 100644
--- a/src/components/HelpPopup.tsx
+++ b/src/components/HelpPopup.tsx
@@ -72,7 +72,7 @@ export function HelpPopup() {
             <strong>x, y</strong> - Pixel coordinates
           </p>
           <p>
-            <strong>t</strong> - Time (enables animation)
+            <strong>t</strong> - Time (enables animation) - also available as t(n) for modulo wrapping
           </p>
           <p>
             <strong>bpm</strong> - Current BPM from tap tempo (default: 120)
@@ -105,6 +105,15 @@ export function HelpPopup() {
 
         <div className="help-section">
           <h4>Core Variables - Advanced</h4>
+          <p>
+            <strong>bx, by</strong> - Block coordinates (16-pixel chunks, great for pixelated effects)
+          </p>
+          <p>
+            <strong>sx, sy</strong> - Signed coordinates (centered at origin, negative to positive)
+          </p>
+          <p>
+            <strong>qx, qy</strong> - Quarter-block coordinates (8-pixel chunks, finer than bx/by)
+          </p>
           <p>
             <strong>n</strong> - Noise value (0.0 to 1.0)
           </p>
@@ -239,20 +248,41 @@ export function HelpPopup() {
             <strong>sin, cos, tan</strong> - Trigonometric functions
           </p>
           <p>
-            <strong>abs, sqrt, pow</strong> - Absolute, square root, power
+            <strong>asin, acos, atan, atan2</strong> - Inverse trigonometric functions
           </p>
           <p>
-            <strong>floor, ceil, round</strong> - Rounding functions
+            <strong>abs, sqrt, cbrt, pow</strong> - Absolute, square root, cube root, power
           </p>
           <p>
-            <strong>min, max</strong> - Minimum and maximum
+            <strong>floor, ceil, round, trunc</strong> - Rounding functions
+          </p>
+          <p>
+            <strong>min, max, sign</strong> - Minimum, maximum, sign (-1/0/1)
+          </p>
+          <p>
+            <strong>log, log10, log2, exp</strong> - Logarithmic and exponential
+          </p>
+          <p>
+            <strong>clamp(val, min, max)</strong> - Constrain value between min and max
+          </p>
+          <p>
+            <strong>lerp(a, b, t)</strong> - Linear interpolation between a and b
+          </p>
+          <p>
+            <strong>smooth(edge, x)</strong> - Smooth step function for gradients
+          </p>
+          <p>
+            <strong>step(edge, x)</strong> - Step function (0 if x&lt;edge, 1 otherwise)
+          </p>
+          <p>
+            <strong>fract(x)</strong> - Fractional part (x - floor(x))
+          </p>
+          <p>
+            <strong>mix(a, b, t)</strong> - Alias for lerp
           </p>
           <p>
             <strong>random</strong> - Random number 0-1
           </p>
-          <p>
-            <strong>log, exp</strong> - Natural logarithm, exponential
-          </p>
           <p>
             <strong>PI, E</strong> - Math constants
           </p>