diff --git a/docs/ALGORITHM.adoc b/docs/ALGORITHM.adoc
index 5ae4c79..035d2e3 100644
--- a/docs/ALGORITHM.adoc
+++ b/docs/ALGORITHM.adoc
@@ -12,71 +12,25 @@
 
 == Data format
 
-[source]
+[source,title='this_algorithm and S2 CellID Format']
 ----
-Example: Face 2, level 23
-
-# Most significant 3 bits are for the face
-face_number = 0b010
-
-# This algorithm is always level 23
-data_bits = level * 2 = 23 * 2 = 46
-
-# The bit after the data bits is always 1
-# All subsequent bits are always 0
-
-Bit                     :  64              48               32              16             1
-                        :  |               |                |               |              |
-                        :  01001011101010001011100010010011 1001001100100l001100000000000000
-Face number             :  ^^^
-Data bits               :     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
-Bit after data bits (1) :                                                    ^
-All remaining bits (0)  :                                                     ^^^^^^^^^^^^^^
+=== this_algorithm Format ===
+WORD3 (13 bits)               :  vvvvvvvvvvvvv
+WORD2 (13 bits)               :  |           |vvv vvvvvvvvvv
+WORD1 (13 bits)               :  |           |             |vvvvvv vvvvvvv
+0000 (10 bits)                :  |           |             |             |vvvvvvvvv v
+Not represented               :  |           |             |             |          |
+                              :  |           |             |             |          |
+Bit                           :  64          52   48       39      32    26         16             1
+                              :  |           |    |        |       |     |          |              |
+                              :  0100101110101000 1011100010010011 1001001100100l00 1100000000000000
+=== S2 CellID Format ===         | |                                                ||             |
+Face number                   :  ^^^                                                ||             |
+Data bits                     :     ^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^ ^|             |
+Bit after data bits (1)       :                                                      ^             |
+All remaining bits (0)        :                                                       ^^^^^^^^^^^^^^
 ----
 
-[source]
-----
-All remaining bits (0)  :                                                     vvvvvvvvvvvvvv
-Bit after data bits (1) :                                                    v
-Data bits               :     vvvvvvvvvvvvvvvvvvvvvvvvvvvvv vvvvvvvvvvvvvvvvv
-Face number             :  vvv
-Bit                     :  64              48               32              16             1
-                        :  |               |                |               |              |
-                        :  01001011101010001011100010010011 1001001100100l001100000000000000
-Not represented         :                                                    ^^^^^^^^^^^^^^^
-0000 (10 bits)          :                                          ^^^^^^^^^^
-WORD1 (13 bits)         :                            ^^^^^^ ^^^^^^^
-WORD2 (13 bits)         :               ^^^^^^^^^^^^^
-WORD3 (13 bits)         :  ^^^^^^^^^^^^^
-----
-
-Alternative format (generated using link:https://github.com/luismartingarcia/protocol[protocol^])
-
-[source]
-----
-./protocol 'Face:3,Data:46,1:1,0:14?bits=32'
- 0                   1                   2                   3
- 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-| Face|                           Data                          |
-+-+-+-+                           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|                                 |1|             0             |
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-----
-
-[source]
-----
-./protocol 'WORD3:13,WORD2:13,WORD1:13,Number:10?bits=32'
- 0                   1                   2                   3
- 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|          WORD3          |          WORD2          |           |
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|    WORD1    |       Number      |
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-----
-
-
 == Encoding
 
 [%header,cols="2m,5a"]
@@ -199,7 +153,14 @@ func cellIDFromFaceIJ(f, i, j int) CellID {
 ----
 [source,rust]
 ----
-fn fij_to_cellid(f: u8, s: u32, t: u32) -> u64 {
+const FACE_BITS: u64 = 3;
+const NUM_FACES: u8 = 6;
+const MAX_LEVEL: u64 = 30;
+const POS_BITS: u64 = (2 * MAX_LEVEL) + 1;
+const MAX_SIZE: u64 = 1 << MAX_LEVEL;
+const WRAP_OFFSET: u64 = (NUM_FACES as u64) << POS_BITS;
+
+fn fij_to_cellid(f: u8, i: u32, j: u32) -> u64 {
     let mut n = u64::from(f) << (POS_BITS - 1);
     let mut bits = u32::from(f & SWAP_MASK);