diff --git a/reactor/Test/test/LogicalHelper.kt b/reactor/Test/test/LogicalHelper.kt
index 215d6e2e..75310932 100644
--- a/reactor/Test/test/LogicalHelper.kt
+++ b/reactor/Test/test/LogicalHelper.kt
@@ -10,6 +10,8 @@ import java.util.*
  */
 
 
+fun <T: Any> anon(value: T) = TestLogical(value)
+
 fun <T: Any> logical(name: String) = TestLogical<T>(name)
 
 fun <T: Any> logical(name1: String, name2: String) = Pair(TestLogical<T>(name1), TestLogical<T>(name2))
@@ -39,6 +41,12 @@ fun <T: Any> Logical<T>.set(t: T) {
 
 data class TestLogical<T>(val name: String, var value: T?, var parent: TestLogical<T>?) : Logical<T> {
 
+    companion object {
+        var anonIdx = 0
+    }
+
+    constructor(value: T) : this("$${anonIdx++}", value, null)
+
     constructor(name: String) : this(name, null, null) {}
 
     override fun name(): String = name
diff --git a/reactor/Test/test/TestProgram.kt b/reactor/Test/test/TestProgram.kt
index 16a49ffb..12ec6648 100644
--- a/reactor/Test/test/TestProgram.kt
+++ b/reactor/Test/test/TestProgram.kt
@@ -123,4 +123,51 @@ class TestProgram {
         }
     }
 
+    @Test
+    fun gcd() {
+        val (M, N, TMP) = logicalPattern<Int>("M", "N", "TMP")
+        program(
+            rule("main",
+                headReplaced(
+                    constraint("main")
+                ),
+                body(
+                    statement({ m, n -> m.set(21); n.set(35) }, M, N),
+                    constraint("gcd", M),
+                    constraint("gcd", N)
+                )
+            ),
+            rule("trivial",
+                headReplaced(
+                    constraint("gcd", M)
+                ),
+                guard(
+                    expression({ x -> x.get() == 0 }, M)
+                ),
+                body(
+                    statement {  } // nothing
+                )
+            ),
+            rule("step",
+                headKept(
+                    constraint("gcd", N)
+                ),
+                headReplaced(
+                    constraint("gcd", M)
+                ),
+                guard(
+                    expression({ m, n -> m.get() >= n.get()}, M, N)
+                ),
+                body(
+                    statement({ m, n, tmp -> tmp.set(m.get() - n.get())}, M, N, TMP),
+                    constraint("gcd", TMP)
+                )
+            )
+        ).session("gcd").run {
+            assertEquals(1, constraintOccurrences().count())
+            val arg = constraintOccurrences().first().arguments().first()
+            assertEquals(7, (arg as Logical<Int>).get())
+        }
+    }
+
 }