diff --git a/old_projects/crypto.py b/old_projects/crypto.py
index f3d09b0b..9dfa48a6 100644
--- a/old_projects/crypto.py
+++ b/old_projects/crypto.py
@@ -5299,7 +5299,7 @@ class Thumbnail(DistributedBlockChainScene):
         block_chain.arrows.highlight(RED)
         block_chain.blocks.gradient_highlight(BLUE, GREEN)
         block_chain.scale_to_fit_width(2*SPACE_WIDTH-1)
-        block_chain.set_stroke(width = 8)
+        block_chain.set_stroke(width = 12)
         self.add(block_chain)