Inverted Pyramids is a 4x4x4 cube in an octahedral. We can solve it like 4x4x4 cube by reduction method. But it is too hard to observe the edge in the different color in reduction method. And in some case, the center pieces will be scramble after our operate.
So reduction method is not a good way to solve the Inverted Pyramids.
I find a way to solve the Inverted Pyramids in some chance. It is easy to observe and well-understand. Even needn't any sequence. So I think it is a easy way.
I solve the Inverted Pyramids in the way that I call it as "Surface Method".
Let learn the Inverted Pyramids' features first.
1. It is a 4x4x4 Cube.
2. When we see it as a 2x2x2 cube, it is non-scrambled cube.
My "Surface Method" is based in this features.
Let us named the pieces in my "Surface Method":
01 Named.JPG [ 105.86 KiB | Viewed 731 times ]
Don't care of architecture, I named the pieces in every side. So the Inverted Pyramids have 1 center, 3 edge and 3 corner in one side. My "Surface Method" is operate by these edge and corner.
First, we can splice one side in very simple operation.
I post 3 pictures to explain:
1. Turn one layer to splice the center to a edge.
02 Side-1.JPG [ 170.71 KiB | Viewed 731 times ]
2. Turn one layer to splice the "center + edge" to a "edge + corner".
02 Side-2.JPG [ 169.5 KiB | Viewed 731 times ]
3. Turn one layer to splice the "middle triangle" to a "line".
02 Side-3.JPG [ 168.03 KiB | Viewed 731 times ]
It is easy to understande without any sequence.
03 Finish 4.gif [ 3.24 KiB | Viewed 731 times ]
We can finish 4-5 side in this way by adjust the sides' position. When we deal with the 6th face, we need a new sequence.
There is a very simple sequence to rotate one corner of a cube:
R F' R' F R F' R' F
The corner piece RFU will turn by this sequence.
This sequence will scramble other pieces, but it won't be affect in the Inverted Pyramids.
04 Turn-1.jpg [ 145.04 KiB | Viewed 731 times ]
04 Turn-2.jpg [ 145.4 KiB | Viewed 731 times ]
So we can use this sequence to turn the other side to solice them.
Let us explain the process by pictures:
1. Turn one layer to splice a part to another part.
05 From-1.jpg [ 109.8 KiB | Viewed 731 times ]
2. Rotate side by the sequence.
05 From-2.jpg [ 114.87 KiB | Viewed 731 times ]
3. Turn one layer back.
05 From-3.JPG [ 110.42 KiB | Viewed 731 times ]
Use this operation repeatedly, we can solve the Inverted Pyramids easy and quickly.