1 files changed, 17 insertions, 0 deletions

diff --git a/src/alg.c b/src/alg.c
index 2b5b93f..6a16d9a 100644
--- a/src/alg.c
+++ b/src/alg.c
@@ -6,6 +6,7 @@ static bool        allowed_HTM(Move m);
 static bool        allowed_URF(Move m);
 static bool        allowed_eofb(Move m);
 static bool        allowed_drud(Move m);
+static bool        allowed_drud_noD(Move m);
 static bool        allowed_htr(Move m);
 static bool        allowed_next_HTM(Move l2, Move l1, Move m);
 static int         axis(Move m);
@@ -46,6 +47,12 @@ moveset_drud = {
 };
 
 Moveset
+moveset_drud_noD = {
+        .allowed      = allowed_drud_noD,
+        .allowed_next = allowed_next_HTM,
+};
+
+Moveset
 moveset_htr = {
         .allowed      = allowed_htr,
         .allowed_next = allowed_next_HTM,
@@ -57,6 +64,7 @@ static Moveset * all_ms[] = {
         &moveset_URF,
         &moveset_eofb,
         &moveset_drud,
+        &moveset_drud_noD,
         &moveset_htr,
 };
 
@@ -95,6 +103,15 @@ allowed_drud(Move m)
 }
 
 static bool
+allowed_drud_noD(Move m)
+{
+        Move b = base_move(m);
+
+        return b == U ||
+               ((b == R || b == L || b == F || b == B) && m == b + 1);
+}
+
+static bool
 allowed_htr(Move m)
 {
         Move b = base_move(m);