diff --git a/mutators.scad b/mutators.scad
index d7de360..cdc4121 100644
--- a/mutators.scad
+++ b/mutators.scad
@@ -105,7 +105,7 @@ module bounding_box(excess=0, planar=false) {
 //   a normal vector.  The s parameter is needed for the module
 //   version to control the size of the masking cube, which affects preview display.
 //   When called as a function, you must supply a vnf, path or region in p.  If planar is set to true for the module version the operation
-//   is performed in  and UP and DOWN are treated as equivalent to BACK and FWD respectively.  
+//   is performed in  and UP and DOWN are treated as equivalent to BACK and FWD respectively.
 //
 // Arguments:
 //   p = path, region or VNF to slice.  (Function version)
@@ -163,7 +163,7 @@ function half_of(p, v=UP, cp) =
       let(
           v = (v==UP)? BACK : (v==DOWN)? FWD : v,
           cp = is_undef(cp) ? [0,0]
-             : is_num(cp) ? v*cp 
+             : is_num(cp) ? v*cp
              : assert(is_vector(cp,2) || (is_vector(cp,3) && cp.z==0),"Centerpoint must be 2-vector")
                cp
       )
@@ -179,7 +179,7 @@ function half_of(p, v=UP, cp) =
       intersection(box,p)
    : assert(false, "Input must be a region, path or VNF");
 
-          
+
 
 /*  This code cut 3d paths but leaves behind connecting line segments
     is_path(p) ?
@@ -824,13 +824,23 @@ module HSL(h,s=1,l=0.5,a=1) color(HSL(h,s,l),a) children();
 //   rgb = HSV(h=270,s=0.75,v=0.9);
 //   color(rgb) cube(60, center=true);
 function HSV(h,s=1,v=1) =
+    assert(s>=0 && s<=1)
+    assert(v>=0 && v<=1)
     let(
-        h=posmod(h,360),
-        v2=v*(1-s),
-        r=lookup(h,[[0,v], [60,v], [120,v2], [240,v2], [300,v], [360,v]]),
-        g=lookup(h,[[0,v2], [60,v], [180,v], [240,v2], [360,v2]]),
-        b=lookup(h,[[0,v2], [120,v2], [180,v], [300,v], [360,v2]])
-    ) [r,g,b];
+        h = posmod(h,360),
+        c = v * s,
+        hprime = h/60,
+        x = c * (1- abs(hprime % 2 - 1)),
+        rgbprime = hprime <=1 ? [c,x,0]
+                 : hprime <=2 ? [x,c,0]
+                 : hprime <=3 ? [0,c,x]
+                 : hprime <=4 ? [0,x,c]
+                 : hprime <=5 ? [x,0,c]
+                 : hprime <=6 ? [c,0,x]
+                 : [0,0,0],
+        m=v-c
+    )
+    rgbprime+[m,m,m];
 
 module HSV(h,s=1,v=1,a=1) color(HSV(h,s,v),a) children();
 
diff --git a/tests/test_vectors.scad b/tests/test_vectors.scad
index 52217ff..e2c6759 100644
--- a/tests/test_vectors.scad
+++ b/tests/test_vectors.scad
@@ -47,6 +47,23 @@ module test_v_ceil() {
 test_v_ceil();
 
 
+module test_v_lookup() {
+    lup = [[4, [3,4,5]], [5, [5,6,7]], [6, [4,5,6]]];
+    assert_equal(v_lookup(3,lup), [3,4,5]);
+    assert_equal(v_lookup(3.5,lup), [3,4,5]);
+    assert_equal(v_lookup(4,lup), [3,4,5]);
+    assert_approx(v_lookup(4.2,lup), [3.4,4.4,5.4]);
+    assert_equal(v_lookup(4.5,lup), [4,5,6]);
+    assert_equal(v_lookup(5,lup), [5,6,7]);
+    assert_approx(v_lookup(5.2,lup), [4.8,5.8,6.8]);
+    assert_equal(v_lookup(5.5,lup), [4.5,5.5,6.5]);
+    assert_equal(v_lookup(6,lup), [4,5,6]);
+    assert_equal(v_lookup(6.5,lup), [4,5,6]);
+    assert_equal(v_lookup(7,lup), [4,5,6]);
+}
+test_v_lookup();
+
+
 module test_v_mul() {
     assert_equal(v_mul([3,4,5], [8,7,6]), [24,28,30]);
     assert_equal(v_mul([1,2,3], [4,5,6]), [4,10,18]);
diff --git a/tutorials/Mutators.md b/tutorials/Mutators.md
index 299fc1e..276b62a 100644
--- a/tutorials/Mutators.md
+++ b/tutorials/Mutators.md
@@ -253,9 +253,11 @@ easier to select colors using other color schemes.  You can use the HSL or Hue-S
 color scheme with the `HSL()` module:
 
 ```openscad
-for (h=[0:0.1:1], s=[0:0.1:1], l=[0:0.1:1]) {
-    translate(100*[h,s,l]) {
-        HSL(h*360,1-s,l) cube(10,center=true);
+n = 10; size = 100/n;
+for (a=count(n), b=count(n), c=count(n)) {
+    let( h=360*a/n, s=1-b/(n-1), l=c/(n-1))
+    translate(size*[a,b,c]) {
+        HSL(h,s,l) cube(size);
     }
 }
 ```
@@ -263,9 +265,11 @@ for (h=[0:0.1:1], s=[0:0.1:1], l=[0:0.1:1]) {
 You can use the HSV or Hue-Saturation-Value color scheme with the `HSV()` module:
 
 ```openscad
-for (h=[0:0.1:1], s=[0:0.1:1], v=[0:0.1:1]) {
-    translate(100*[h,s,v]) {
-        HSV(h*360,1-s,v) cube(10,center=true);
+n = 10; size = 100/n;
+for (a=count(n), b=count(n), c=count(n)) {
+    let( h=360*a/n, s=1-b/(n-1), v=c/(n-1))
+    translate(size*[a,b,c]) {
+        HSV(h,s,v) cube(size);
     }
 }
 ```
diff --git a/vectors.scad b/vectors.scad
index 4bbfed7..25498b1 100644
--- a/vectors.scad
+++ b/vectors.scad
@@ -107,6 +107,31 @@ function v_ceil(v) =
     [for (x=v) ceil(x)];
 
 
+// Function: v_lookup()
+// Description:
+//   Works just like the built-in function [`lookup()`](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Mathematical_Functions#lookup), except that it can also interpolate between vector result values of the same length.
+// Arguments:
+//   x = The scalar value to look up.
+//   v = A list of [KEY,VAL] pairs. KEYs are scalars.  VALs should either all be scalar, or all be vectors of the same length.
+// Example:
+//   x = v_lookup(4.5, [[4, [3,4,5]], [5, [5,6,7]]]);  // Returns: [4,5,6]
+function v_lookup(x, v) =
+    is_num(v[0][1])? lookup(x,v) :
+    let(
+        i = lookup(x, [for (i=idx(v)) [v[i].x,i]]),
+        vlo = v[floor(i)],
+        vhi = v[ceil(i)],
+        lo = vlo[1],
+        hi = vhi[1]
+    )
+    assert(is_vector(lo) && is_vector(hi),
+        "Result values must all be numbers, or all be vectors.")
+    assert(len(lo) == len(hi), "Vector result values must be the same length")
+    vlo.x == vhi.x? vlo[1] :
+    let( u = (x - vlo.x) / (vhi.x - vlo.x) )
+    lerp(lo,hi,u);
+
+
 // Function: unit()
 // Usage:
 //   unit(v, [error]);