The figures look like they are part of the log.
But the tower posts look like they don't follow the grain at all. The growth rings curve around at the bottom of the picture like you would expect them to, but the tower posts are vertical grain. And tower A grain is uphill grain facing you, tower B is downhill grain facing you, and C is also uphill facing you.
The only way that could be part of the log is if there happened to be a limb growing there.
