diff --git a/examples/prime_sequence_generator.gr b/examples/prime_sequence_generator.gr
index 1cffc975..fe70c3fb 100644
--- a/examples/prime_sequence_generator.gr
+++ b/examples/prime_sequence_generator.gr
@@ -2,42 +2,35 @@
 
 func primesGen(maxSieve) {
     sieve = [true] * maxSieve
-    num = 2
-    currentPrime = 2
+    prime = 2
     nextPrime = () => {
-        for currentPrime < maxSieve {
-            if sieve[currentPrime] {
-                prime = currentPrime
-                currentPrime++
-                mult = prime * prime
+        for prime < maxSieve {
+            if sieve[prime] {
+                p = prime++
+                mult = p * p
                 for max(maxSieve - mult, 0) {
-                    if mult % prime == 0 {
+                    if mult % p == 0 {
                         sieve[mult] = false
                     }
                     mult++
                 }
-                return prime
+                return p
             } else {
-                currentPrime++
+                prime++
             }
         }
-        return nil
+        nil
     }
 }
 
 
 maxS = 1000 // use 100_000 for profiling.
 primeIter = primesGen(maxS)
-p = primeIter()
-printf("| %4d", p)
-n = 1
-for p <= maxS {
-    p = primeIter()
-    if p != nil {
-        printf(" %4d", p)
-        if ++n % 15 == 0 {
-            print("\n|")
-        }
+n = 0
+for (p = primeIter()) != nil {
+    if n++ % 15 == 0 {
+        print("\n|")
     }
+    printf(" %4d", p)
 }
 println()
diff --git a/go.mod b/go.mod
index 382248fb..191f58ae 100644
--- a/go.mod
+++ b/go.mod
@@ -8,7 +8,7 @@ require (
 	fortio.org/sets v1.2.0
 	fortio.org/struct2env v0.4.1
 	fortio.org/terminal v0.8.2
-	fortio.org/testscript v0.3.1 // only for tests
+	fortio.org/testscript v0.3.2 // only for tests
 	fortio.org/version v1.0.4
 	github.com/rivo/uniseg v0.4.7
 )
diff --git a/go.sum b/go.sum
index 3562ee27..4df7a762 100644
--- a/go.sum
+++ b/go.sum
@@ -12,8 +12,8 @@ fortio.org/term v0.23.0-fortio-6 h1:pKrUX0tKOxyEhkhLV50oJYucTVx94rzFrXc24lIuLvk=
 fortio.org/term v0.23.0-fortio-6/go.mod h1:7buBfn81wEJUGWiVjFNiUE/vxWs5FdM9c7PyZpZRS30=
 fortio.org/terminal v0.8.2 h1:kluLHjxsuflyRpkp9HzVM5Df8mbiX1tdDRN9Jdlp2M4=
 fortio.org/terminal v0.8.2/go.mod h1:4mFl6U7FmnQ+D/NZuxq05QDX/guBTwCRb2+DxTOj4Tg=
-fortio.org/testscript v0.3.1 h1:MmRO64AsmzaU1KlYMzAbotJIMKRGxD1XXssJnBRiMGQ=
-fortio.org/testscript v0.3.1/go.mod h1:7OJ+U4avooRNqc7p/VHKJadYgj9fA6+N0SbGU8FVWGs=
+fortio.org/testscript v0.3.2 h1:ks5V+Y6H6nmeGqnVlZuLdiFwpqXemDkEnyGgCZa/ZNA=
+fortio.org/testscript v0.3.2/go.mod h1:Z2kUvEDHYETV8FLxsdA6zwSZ8sZUiTNJh2Dw5c4a3Pg=
 fortio.org/version v1.0.4 h1:FWUMpJ+hVTNc4RhvvOJzb0xesrlRmG/a+D6bjbQ4+5U=
 fortio.org/version v1.0.4/go.mod h1:2JQp9Ax+tm6QKiGuzR5nJY63kFeANcgrZ0osoQFDVm0=
 github.com/kortschak/goroutine v1.1.2 h1:lhllcCuERxMIK5cYr8yohZZScL1na+JM5JYPRclWjck=