diff --git a/site/src/tutorial.rs b/site/src/tutorial.rs
index f34c1ad0..40a8c7ca 100644
--- a/site/src/tutorial.rs
+++ b/site/src/tutorial.rs
@@ -1019,8 +1019,8 @@ fn TutorialAdvancedStack() -> impl IntoView {
         <Editor example="+dggdp 1 2 3 4 5"/>
         <p>"In general, planet notation as complex as the mathematical function example above should only be used when it is necessary. For examples like that with 4+ values, it is. However, when working with fewer values, you can get very far with just "<Prim prim=Dup/>" and "<Prim prim=Flip/>". Maybe sprinkle some "<Prim prim=Over/>"s and "<Prim prim=Dip/>"s in there too."</p>
 
-        <Hd id="on"><Prim prim=On/></Hd>
-        <p>"As you write more Uiua code, you'll find that there is a pattern you'll encounter over and over again. It involves calling a function, then calling another function that re-uses an argument to the first function."</p>
+        <Hd id="on-and-by"><Prim prim=On/>" and "<Prim prim=By/></Hd>
+        <p>"As you write more Uiua code, you'll find that there is a kind of pattern you'll encounter over and over again. It involves calling a function, then calling another function that re-uses an argument to the first function."</p>
         <p>"One simple example is getting "<code>"n"</code>" numbers between "<code>"0"</code>" and "<code>"1"</code>". One way you may think to solve this is with "<Prim prim=Dup/>" and "<Prim prim=Flip/>"."</p>
         <Editor example="÷:⇡. 5"/> // Should fail
         <p>"This solution works, but as the style diagnostic suggests, it is not quite idiomatic."</p>
diff --git a/src/algorithm/mod.rs b/src/algorithm/mod.rs
index f754d72d..ac3d2e24 100644
--- a/src/algorithm/mod.rs
+++ b/src/algorithm/mod.rs
@@ -276,10 +276,10 @@ where
         return Ok(());
     }
     if expand_fixed && arr.row_count() == 1 && ctx.scalar_fill::<T>().is_err() {
-        let fixes = (arr.shape.iter())
-            .take_while(|&&dim| dim == 1)
-            .count()
-            .min(arr.shape.len());
+        let mut fixes = (arr.shape.iter()).take_while(|&&dim| dim == 1).count();
+        if fixes == arr.rank() {
+            fixes = (fixes - 1).max(1)
+        }
         let same_under_fixes = (target.iter().skip(fixes))
             .zip(arr.shape[fixes..].iter())
             .all(|(b, a)| b == a);
@@ -402,7 +402,7 @@ where
             }
             let a_shape = a.shape().clone();
             let b_shape = b.shape().clone();
-            let a_err = fill_array_shape(a, b.shape(), true, ctx).err();
+            let a_err = fill_array_shape(a, &b_shape, true, ctx).err();
             let b_err = fill_array_shape(b, &a_shape, true, ctx).err();
             if shape_prefixes_match(&a.shape, &b.shape) {
                 Ok(())
diff --git a/src/algorithm/pervade.rs b/src/algorithm/pervade.rs
index 8b6f2feb..b3d00cf1 100644
--- a/src/algorithm/pervade.rs
+++ b/src/algorithm/pervade.rs
@@ -112,7 +112,7 @@ where
         // A is fixed
         if a.row_count() == 1 && b.row_count() != 1 {
             let fix_count = a.shape.iter().take_while(|&&d| d == 1).count();
-            if b.rank() > fix_count {
+            if b.rank() > fix_count && b.rank() >= a.rank() {
                 if (a.shape().iter())
                     .zip(b.shape())
                     .skip(fix_count)
@@ -148,7 +148,7 @@ where
         // B is fixed
         if a.row_count() != 1 && b.row_count() == 1 {
             let fix_count = b.shape.iter().take_while(|&&d| d == 1).count();
-            if a.rank() > fix_count {
+            if a.rank() > fix_count && a.rank() >= b.rank() {
                 if (a.shape().iter())
                     .zip(b.shape())
                     .skip(fix_count)
diff --git a/tests/units.ua b/tests/units.ua
index 71f60409..9bd32749 100644
--- a/tests/units.ua
+++ b/tests/units.ua
@@ -14,16 +14,16 @@
 ⍤⟜≍: ↯2_0_2e ×2↯2_0_2e
 
 # Fixed pervasive math
-+ ¤100_200 [[1_2 3_4] [5_6 7_8] [9_10 11_12]]
-⍤⟜≍: [[101_102 203_204] [105_106 207_208] [109_110 211_212]]
-+ ¤¤100_200 [[1_2 3_4] [5_6 7_8] [9_10 11_12]]
-⍤⟜≍: [[101_202 103_204] [105_206 107_208] [109_210 111_212]]
-⍤⟜≍: [11_12_13 24_25_26] + 10_20 [1_2_3 4_5_6]
-⍤⟜≍: [11_22_33 14_25_36] + ¤10_20_30 [1_2_3 4_5_6]
-⍤⟜≍: [3_2_1 4_3_2 5_4_3] - ¤[1 2 3] [4 5 6]
+⍤⟜≍: ⊃≡++ ¤100_200 [[1_2 3_4] [5_6 7_8] [9_10 11_12]]
+⍤⟜≍: ⊃≡≡++ ¤¤100_200 [[1_2 3_4] [5_6 7_8] [9_10 11_12]]
+⍤⟜≍: ⊃≡++ 10_20 [1_2_3 4_5_6]
+⍤⟜≍: ⊃≡++ ¤10_20_30 [1_2_3 4_5_6]
+⍤⟜≍: ⊃≡-- ¤[1 2 3] [4 5 6]
 ⍤⟜≍: 0_3 △ +¤ ↯3 0 ↯0_3 0
 ⍤⟜≍: 1_3 △ +¤ ↯3 0 ↯1_3 0
-⍤⟜≍: ⇡10 + ¤¤0 ⇡10
+⍤⟜≍: ⊃≡≡++ ¤¤0 ⇡10
+⍤⟜≍: ⊃≡++ [0_1_2 3_4_5] ¤ [0_3_6 1_4_7 2_5_8]
+⍤⟜≍: ⊃≡++ ¤ [0_1_2 3_4_5 6_7_8] [0_3_6 1_4_7 2_5_8]
 ⍤⟜≍: [11_12_13 21_22_23 31_32_33 41_42_43] + ¤[1 2 3] [10 20 30 40]
 ⍤⟜≍: [11_21_31_41 12_22_32_42 13_23_33_43] + ⊙¤[1 2 3] [10 20 30 40]
 ⍤⟜≍: [11_22_33 41_52_63] + ¤[1 2 3] [10_20_30 40_50_60]