diff --git a/src/tea3/cli.py b/src/tea3/cli.py
index a4b965a..2a4c519 100644
--- a/src/tea3/cli.py
+++ b/src/tea3/cli.py
@@ -23,19 +23,37 @@ def main() -> None:
     steps = prompt_int("\nHow many steps do you want to run? (1–100): ", 1, 100)
 
     print("\nR registers are indexed 0–7; bits within each register are 0–7.")
-    reg = prompt_int("Which R register do you want to inspect? (0–7): ", 0, 7)
-    bit = prompt_int("Which bit of that register?              (0–7): ", 0, 7)
+    print("Enter -1 to print all registers, or all bits.")
+
+    reg = prompt_int("Which R register do you want to inspect? (-1 or 0–7): ", -1, 7)
+    bit = prompt_int("Which bit of that register?              (-1 or 0–7): ", -1, 7)
+
+    if reg == -1 and bit == -1:
+        print(f"\nRunning {steps} step(s), watching all R registers and all bits")
+    elif reg == -1:
+        print(f"\nRunning {steps} step(s), watching all R registers, bit [{bit}]")
+    elif bit == -1:
+        print(f"\nRunning {steps} step(s), watching R[{reg}] and all bits")
+    else:
+        print(f"\nRunning {steps} step(s), watching R[{reg}][{bit}]")
 
-    print(f"\nRunning {steps} step(s), watching R[{reg}][{bit}]")
     print("-" * 50)
 
     model = Tea3Model()
 
     for i in range(steps):
         model.step()
-        poly = model.R_bits[reg][bit]
-        print(f"\n[Step {i+1}]  R_bits[{reg}][{bit}] =")
-        print(pretty_print(poly))
+        print(f"\n[Step {i + 1}]")
+
+        regs = range(8) if reg == -1 else [reg]
+        bits = range(8) if bit == -1 else [bit]
+
+        for r in regs:
+            for b in bits:
+                poly = model.R_bits[r][b]
+                print(f"R_bits[{r}][{b}] =")
+                print(pretty_print(poly))
+                print()
 
     print("\n" + "=" * 50)
     print("Done.")