diff --git a/src/core/pattern.js b/src/core/pattern.js
index 0321e1b4b..c6721af59 100644
--- a/src/core/pattern.js
+++ b/src/core/pattern.js
@@ -508,29 +508,32 @@ Shadings.Mesh = (function MeshClosure() {
           break;
         case 1:
           tmp1 = ps[12]; tmp2 = ps[13]; tmp3 = ps[14]; tmp4 = ps[15];
-          ps[12] = pi + 5; ps[13] = pi + 4;  ps[14] = pi + 3;  ps[15] = pi + 2;
-          ps[ 8] = pi + 6; /* values for 5, 6, 9, 10 are    */ ps[11] = pi + 1;
-          ps[ 4] = pi + 7; /* calculated below              */ ps[ 7] = pi;
-          ps[ 0] = tmp1;   ps[ 1] = tmp2;    ps[ 2] = tmp3;    ps[ 3] = tmp4;
+          ps[12] = tmp4; ps[13] = pi + 0;  ps[14] = pi + 1;  ps[15] = pi + 2;
+          ps[ 8] = tmp3; /* values for 5, 6, 9, 10 are    */ ps[11] = pi + 3;
+          ps[ 4] = tmp2; /* calculated below              */ ps[ 7] = pi + 4;
+          ps[ 0] = tmp1; ps[ 1] = pi + 7;   ps[ 2] = pi + 6; ps[ 3] = pi + 5;
           tmp1 = cs[2]; tmp2 = cs[3];
-          cs[2] = ci + 1; cs[3] = ci;
-          cs[0] = tmp1;   cs[1] = tmp2;
+          cs[2] = tmp2;   cs[3] = ci;
+          cs[0] = tmp1;   cs[1] = ci + 1;
           break;
         case 2:
-          ps[12] = ps[15]; ps[13] = pi + 7; ps[14] = pi + 6;   ps[15] = pi + 5;
-          ps[ 8] = ps[11]; /* values for 5, 6, 9, 10 are    */ ps[11] = pi + 4;
-          ps[ 4] = ps[7];  /* calculated below              */ ps[ 7] = pi + 3;
-          ps[ 0] = ps[3];  ps[ 1] = pi;     ps[ 2] = pi + 1;   ps[ 3] = pi + 2;
-          cs[2] = cs[3]; cs[3] = ci + 1;
-          cs[0] = cs[1]; cs[1] = ci;
+          tmp1 = ps[15];
+          tmp2 = ps[11];
+          ps[12] = ps[3];  ps[13] = pi + 0; ps[14] = pi + 1;   ps[15] = pi + 2;
+          ps[ 8] = ps[7];  /* values for 5, 6, 9, 10 are    */ ps[11] = pi + 3;
+          ps[ 4] = tmp2;   /* calculated below              */ ps[ 7] = pi + 4;
+          ps[ 0] = tmp1;  ps[ 1] = pi + 7;   ps[ 2] = pi + 6;  ps[ 3] = pi + 5;
+          tmp1 = cs[3];
+          cs[2] = cs[1]; cs[3] = ci;
+          cs[0] = tmp1;  cs[1] = ci + 1;
           break;
         case 3:
-          ps[12] = ps[0];  ps[13] = ps[1];   ps[14] = ps[2];   ps[15] = ps[3];
-          ps[ 8] = pi;     /* values for 5, 6, 9, 10 are    */ ps[11] = pi + 7;
-          ps[ 4] = pi + 1; /* calculated below              */ ps[ 7] = pi + 6;
-          ps[ 0] = pi + 2; ps[ 1] = pi + 3;  ps[ 2] = pi + 4;  ps[ 3] = pi + 5;
-          cs[2] = cs[0]; cs[3] = cs[1];
-          cs[0] = ci;    cs[1] = ci + 1;
+          ps[12] = ps[0];  ps[13] = pi + 0;   ps[14] = pi + 1; ps[15] = pi + 2;
+          ps[ 8] = ps[1];  /* values for 5, 6, 9, 10 are    */ ps[11] = pi + 3;
+          ps[ 4] = ps[2];  /* calculated below              */ ps[ 7] = pi + 4;
+          ps[ 0] = ps[3];  ps[ 1] = pi + 7;   ps[ 2] = pi + 6; ps[ 3] = pi + 5;
+          cs[2] = cs[0]; cs[3] = ci;
+          cs[0] = cs[1]; cs[1] = ci + 1;
           break;
       }
       // set p11, p12, p21, p22
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 165920653..cc9337416 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -127,6 +127,7 @@
 !bug946506.pdf
 !issue3885.pdf
 !bug859204.pdf
+!coons-allflags-withfunction.pdf
 !issue4246.pdf
 !issue4461.pdf
 !issue4573.pdf
diff --git a/test/pdfs/coons-allflags-withfunction.pdf b/test/pdfs/coons-allflags-withfunction.pdf
new file mode 100644
index 000000000..fcbf775dc
Binary files /dev/null and b/test/pdfs/coons-allflags-withfunction.pdf differ
diff --git a/test/test_manifest.json b/test/test_manifest.json
index b91a6a9a1..ff7efb60b 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -2247,6 +2247,12 @@
        "lastPage": 4,
        "type": "eq"
     },
+    {  "id": "issue4227",
+       "file": "pdfs/coons-allflags-withfunction.pdf",
+       "md5": "c5f79c24bf9eb66698be0e4ecaa1bdf8",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue4246",
       "file": "pdfs/issue4246.pdf",
       "md5": "ed81787b83cc317c9f049643b853bea3",