Single rope used to create two lines

Anyone have a step-by-step guide to tie this…

Tie an alpine butterfly on the rope, approximately 4ft from the middle mark, and clip it to the left-hand bolt with a locking carabiner.

Back that up with an eight-on-a-bight, tied approximately 9in from the middle mark, clipped to the right-hand bolt.

Repeat on the opposite side of the middle mark, using the correspondingly opposite carabiners.

Lock the carabiners.   Milk the butterflies if you care to(*).

For extra credit/paranoia, orient the carabiners with the screwgates tightened by gravity (unlike as depicted).

*: yes, I'm aware that butterflies do not have nipples.

Edit to add: it isn't crystal clear that the larger loop knots are actually alpine butterflies but that seems like a good choice.

Edit again to add: I find that it is faster and easier to tie an alpine butterfly when the rope is already hanging from a fixed point, so you might want to tie the backups first.   You'll get the same result.   Also the first backup will prevent you from dropping the rope.  :-)

I’m a little confused as to what the extra complexity of this anchor gets you over fixing each bolt with a butterfly or an 8 on a bite or just creating a master point and fixing the middle with an 8? I guess this equalizes both bolts on each strand, but do you really need equalization? If they are modern bolts the likelihood of failure is low and this just seems like extra work and honestly looks like a cluster. A little slack between each isn’t going to have any meaningful impact on the safety of the system. If the bolts are that sketch that your worried about failure during TR solo, rapping or jugging loads they probably need to be replaced.

Dan Bachen wrote:

I’m a little confused as to what the extra complexity of this anchor gets you over fixing each bolt with a butterfly or an 8 on a bite or just creating a master point and fixing the middle with an 8? I guess this equalizes both bolts on each strand, but do you really need equalization? If they are modern bolts the likelihood of failure is low and this just seems like extra work and honestly looks like a cluster. A little slack between each isn’t going to have any meaningful impact on the safety of the system. If the bolts are that sketch that your worried about failure during TR solo, rapping or jugging loads they probably need to be replaced.

Yeah, I was/am also confused.

The best I can come up with is heavy loads (thus the butterflies) on static lines (thus the need to minimize extension)?  Maybe OP will fill us in.

Why not just a figure 8 BFK (like is commonly used as a TR masterpoint) with one loop to each bolt? That way each rope is on both bolts. If the answer is, "But what if the BFK blows up?", then I think there's a bit of unjustified paranoia happening. Example:

Simpler yet is a bunny ears F8. Despite what you've heard, the loops are independent (cut/release one and the other does NOT pull through):And simplest of all, two F8s. Loads are on single bolts, albeit loosely backing each other up:

Even better why not just use a figure 8 with bunny ears? Which can be equalized and then u have 2 strands to work with and fixed to both bolts? Simple and effective!

Thank you all for the comments. This came from Andy Kirkpatrick’s On the line book- top rope solo manual. So, I’d have to ask Andy why the over complexity. Thanks again for all of the feedback!