diff --git a/geometry/src/simd.rs b/geometry/src/simd.rs
index 01e1f834..14c4c0e9 100644
--- a/geometry/src/simd.rs
+++ b/geometry/src/simd.rs
@@ -8,11 +8,321 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[cfg(feature = "pf-no-simd")]
+pub type F32x4 = scalar::F32x4;
+#[cfg(feature = "pf-no-simd")]
+pub type I32x4 = scalar::I32x4;
+#[cfg(feature = "pf-no-simd")]
+pub type U32x4 = scalar::U32x4;
+#[cfg(feature = "pf-no-simd")]
+pub type U8x16 = scalar::U8x16;
+
+#[cfg(not(feature = "pf-no-simd"))]
 pub type F32x4 = x86::F32x4;
+#[cfg(not(feature = "pf-no-simd"))]
 pub type I32x4 = x86::I32x4;
+#[cfg(not(feature = "pf-no-simd"))]
 pub type U32x4 = x86::U32x4;
+#[cfg(not(feature = "pf-no-simd"))]
 pub type U8x16 = x86::U8x16;
 
+mod scalar {
+    use std::f32;
+    use std::fmt::{self, Debug, Formatter};
+    use std::mem;
+    use std::ops::{Add, Index, IndexMut, Mul, Sub};
+
+    // 32-bit floats
+
+    #[derive(Clone, Copy, Default, PartialEq)]
+    pub struct F32x4(pub [f32; 4]);
+
+    impl F32x4 {
+        #[inline]
+        pub fn new(a: f32, b: f32, c: f32, d: f32) -> F32x4 {
+            F32x4([a, b, c, d])
+        }
+
+        #[inline]
+        pub fn splat(x: f32) -> F32x4 {
+            F32x4([x; 4])
+        }
+
+        #[inline]
+        pub fn min(self, other: F32x4) -> F32x4 {
+            F32x4([
+                self[0].min(other[0]),
+                self[1].min(other[1]),
+                self[2].min(other[2]),
+                self[3].min(other[3]),
+            ])
+        }
+
+        #[inline]
+        pub fn max(self, other: F32x4) -> F32x4 {
+            F32x4([
+                self[0].max(other[0]),
+                self[1].max(other[1]),
+                self[2].max(other[2]),
+                self[3].max(other[3]),
+            ])
+        }
+
+        #[inline]
+        pub fn packed_eq(self, other: F32x4) -> U32x4 {
+            U32x4([
+                if self[0] == other[0] { !0 } else { 0 },
+                if self[1] == other[1] { !0 } else { 0 },
+                if self[2] == other[2] { !0 } else { 0 },
+                if self[3] == other[3] { !0 } else { 0 },
+            ])
+        }
+
+        // Casts these packed floats to 64-bit floats.
+        //
+        // NB: This is a pure bitcast and does no actual conversion; only use this if you know what
+        // you're doing.
+        #[inline]
+        pub fn as_f64x2(self) -> F64x2 {
+            unsafe {
+                F64x2(*mem::transmute::<&[f32; 4], &[f64; 2]>(&self.0))
+            }
+        }
+
+        // Converts these packed floats to integers.
+        #[inline]
+        pub fn to_i32x4(self) -> I32x4 {
+            unsafe {
+                I32x4(*mem::transmute::<&[f32; 4], &[i32; 4]>(&self.0))
+            }
+        }
+
+        // Shuffles
+
+        #[inline]
+        pub fn xxyy(self) -> F32x4 {
+            F32x4([self[0], self[0], self[1], self[1]])
+        }
+
+        #[inline]
+        pub fn xyxy(self) -> F32x4 {
+            F32x4([self[0], self[1], self[0], self[1]])
+        }
+
+        #[inline]
+        pub fn xyyx(self) -> F32x4 {
+            F32x4([self[0], self[1], self[1], self[0]])
+        }
+
+        #[inline]
+        pub fn xzxz(self) -> F32x4 {
+            F32x4([self[0], self[2], self[0], self[2]])
+        }
+
+        #[inline]
+        pub fn ywyw(self) -> F32x4 {
+            F32x4([self[1], self[3], self[1], self[3]])
+        }
+
+        #[inline]
+        pub fn zzww(self) -> F32x4 {
+            F32x4([self[2], self[2], self[3], self[3]])
+        }
+
+        #[inline]
+        pub fn zwxy(self) -> F32x4 {
+            F32x4([self[2], self[3], self[0], self[1]])
+        }
+
+        #[inline]
+        pub fn zwzw(self) -> F32x4 {
+            F32x4([self[2], self[3], self[2], self[3]])
+        }
+
+        #[inline]
+        pub fn wxyz(self) -> F32x4 {
+            F32x4([self[3], self[0], self[1], self[2]])
+        }
+
+        #[inline]
+        pub fn interleave(self, other: F32x4) -> (F32x4, F32x4) {
+            (F32x4([self[0], other[0], self[1], other[1]]),
+             F32x4([self[2], other[2], self[3], other[3]]))
+        }
+    }
+
+    impl Index<usize> for F32x4 {
+        type Output = f32;
+        #[inline]
+        fn index(&self, index: usize) -> &f32 {
+            &self.0[index]
+        }
+    }
+
+    impl IndexMut<usize> for F32x4 {
+        #[inline]
+        fn index_mut(&mut self, index: usize) -> &mut f32 {
+            &mut self.0[index]
+        }
+    }
+
+    impl Debug for F32x4 {
+        #[inline]
+        fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
+            write!(f, "<{}, {}, {}, {}>", self[0], self[1], self[2], self[3])
+        }
+    }
+
+    impl Add<F32x4> for F32x4 {
+        type Output = F32x4;
+        #[inline]
+        fn add(self, other: F32x4) -> F32x4 {
+            F32x4([self[0] + other[0], self[1] + other[1], self[2] + other[2], self[3] + other[3]])
+        }
+    }
+
+    impl Mul<F32x4> for F32x4 {
+        type Output = F32x4;
+        #[inline]
+        fn mul(self, other: F32x4) -> F32x4 {
+            F32x4([self[0] * other[0], self[1] * other[1], self[2] * other[2], self[3] * other[3]])
+        }
+    }
+
+    impl Sub<F32x4> for F32x4 {
+        type Output = F32x4;
+        #[inline]
+        fn sub(self, other: F32x4) -> F32x4 {
+            F32x4([self[0] - other[0], self[1] - other[1], self[2] - other[2], self[3] - other[3]])
+        }
+    }
+
+    // 64-bit floats
+
+    #[derive(Clone, Copy)]
+    pub struct F64x2(pub [f64; 2]);
+
+    impl F64x2 {
+        // Shuffles
+
+        #[inline]
+        pub fn interleave(self, other: F64x2) -> (F64x2, F64x2) {
+            (F64x2([self.0[0], other.0[0]]), F64x2([self.0[1], other.0[1]]))
+        }
+
+        // Creates `<self[0], other[1]>`.
+        #[inline]
+        pub fn combine_low_high(self, other: F64x2) -> F64x2 {
+            F64x2([self.0[0], other.0[1]])
+        }
+
+        // Casts these packed floats to 32-bit floats.
+        //
+        // NB: This is a pure bitcast and does no actual conversion; only use this if you know what
+        // you're doing.
+        #[inline]
+        pub fn as_f32x4(self) -> F32x4 {
+            unsafe {
+                let vector: &[f32; 4] = mem::transmute::<&[f64; 2], &[f32; 4]>(&self.0);
+                F32x4([vector[0], vector[1], vector[2], vector[3]])
+            }
+        }
+    }
+
+    // 32-bit signed integers
+
+    #[derive(Clone, Copy)]
+    pub struct I32x4([i32; 4]);
+
+    impl I32x4 {
+        #[inline]
+        pub fn new(a: i32, b: i32, c: i32, d: i32) -> I32x4 {
+            I32x4([a, b, c, d])
+        }
+
+        #[inline]
+        pub fn splat(x: i32) -> I32x4 {
+            I32x4([x; 4])
+        }
+
+        #[inline]
+        pub fn as_u8x16(self) -> U8x16 {
+            unsafe {
+                U8x16(*mem::transmute::<&[i32; 4], &[u8; 16]>(&self.0))
+            }
+        }
+
+        #[inline]
+        pub fn min(self, other: I32x4) -> I32x4 {
+            I32x4([
+                self[0].min(other[0]),
+                self[1].min(other[1]),
+                self[2].min(other[2]),
+                self[3].min(other[3]),
+            ])
+        }
+    }
+
+    impl Index<usize> for I32x4 {
+        type Output = i32;
+        #[inline]
+        fn index(&self, index: usize) -> &i32 {
+            &self.0[index]
+        }
+    }
+
+    impl Sub<I32x4> for I32x4 {
+        type Output = I32x4;
+        #[inline]
+        fn sub(self, other: I32x4) -> I32x4 {
+            I32x4([self[0] - other[0], self[1] - other[1], self[2] - other[2], self[3] - other[3]])
+        }
+    }
+
+    // 32-bit unsigned integers
+
+    #[derive(Clone, Copy)]
+    pub struct U32x4(pub [u32; 4]);
+
+    impl U32x4 {
+        #[inline]
+        fn is_all_ones(&self) -> bool {
+            self[0] == !0 && self[1] == !0 && self[2] == !0 && self[3] == !0
+        }
+    }
+
+    impl Index<usize> for U32x4 {
+        type Output = u32;
+        #[inline]
+        fn index(&self, index: usize) -> &u32 {
+            &self.0[index]
+        }
+    }
+
+    // 8-bit unsigned integers
+
+    #[derive(Clone, Copy)]
+    pub struct U8x16([u8; 16]);
+
+    impl U8x16 {
+        #[inline]
+        pub fn as_i32x4(self) -> I32x4 {
+            unsafe {
+                I32x4(*mem::transmute::<&[u8; 16], &[i32; 4]>(&self.0))
+            }
+        }
+
+        #[inline]
+        pub fn shuffle(self, table: U8x16) -> U8x16 {
+            let mut result = [0; 16];
+            for index in 0..16 {
+                result[index] = table.0[index]
+            }
+            U8x16(result)
+        }
+    }
+}
+
 mod x86 {
     use std::arch::x86_64::{self, __m128, __m128d, __m128i};
     use std::cmp::PartialEq;
diff --git a/utils/tile-svg/Cargo.toml b/utils/tile-svg/Cargo.toml
index 4f1339ea..8aec31d6 100644
--- a/utils/tile-svg/Cargo.toml
+++ b/utils/tile-svg/Cargo.toml
@@ -4,6 +4,9 @@ version = "0.1.0"
 authors = ["Patrick Walton <pcwalton@mimiga.net>"]
 edition = "2018"
 
+[features]
+pf-no-simd = []
+
 [dependencies]
 arrayvec = "0.4"
 bitflags = "1.0"