Setting the comms of a starless flag aside, one possibility for this phenomenon is this:
The white stars are probably sewn onto these flags. That means there's a blue layer of fabric between the stars. When bright light shines through white fabric, you will mainly see the blue color that's in between.
Setting the comms of a starless flag aside, one possibility for this phenomenon is this:
The white stars are probably sewn onto these flags. That means there's a blue layer of fabric between the stars. When bright light shines through white fabric, you will mainly see the blue color that's in between.