diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index d058286..f416b02 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -37,6 +37,8 @@ jobs:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
       - uses: julia-actions/cache@v2
+      - name: registry_add
+        run: julia -e 'using Pkg; Pkg.Registry.add(Pkg.Registry.RegistrySpec(url="https://github.com/MurrellGroup/MurrellGroupRegistry"))'
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
@@ -62,6 +64,8 @@ jobs:
         shell: julia --project=docs --color=yes {0}
         run: |
           using Pkg
+          Pkg.Registry.add(Pkg.Registry.RegistrySpec(url="https://github.com/JuliaRegistries/General"))
+          Pkg.Registry.add(Pkg.Registry.RegistrySpec(url="https://github.com/MurrellGroup/MurrellGroupRegistry"))
           Pkg.develop(PackageSpec(path=pwd()))
           Pkg.instantiate()
       - uses: julia-actions/julia-buildpkg@v1
diff --git a/Project.toml b/Project.toml
index aec8d16..1bc566c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,34 +1,20 @@
 name = "CannotWaitForTheseOptimisers"
 uuid = "16124dda-d9fe-413b-a880-e3f4df3aa341"
-authors = ["murrellb <murrellb@gmail.com> and contributors"]
 version = "0.1.1"
+authors = ["murrellb <murrellb@gmail.com> and contributors"]
+
+[workspace]
+projects = ["test", "docs"]
 
 [deps]
+Functors = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
+MatrixSign = "a25fa8c1-e8fe-40fb-8be2-d139e369b1d5"
 Optimisers = "3bd65402-5787-11e9-1adc-39752487f4e2"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [compat]
-ChainRulesCore = "1"
-Functors = "0.5"
-LinearAlgebra = "1"
+Functors = "0.5.2"
+MatrixSign = "0.0.1"
 Optimisers = "0.4"
 Random = "1"
-StaticArrays = "1"
-Statistics = "1"
-Test = "1"
-Zygote = "0.6"
 julia = "1.10"
-
-[extras]
-Optimisers = "3bd65402-5787-11e9-1adc-39752487f4e2"
-Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
-Functors = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
-LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
-Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
-StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
-Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
-Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
-
-[targets]
-test = ["Test", "ChainRulesCore", "Functors", "LinearAlgebra", "Optimisers", "StaticArrays", "Statistics", "Zygote"]
diff --git a/docs/src/index.md b/docs/src/index.md
index 17345db..7f028ab 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -12,3 +12,9 @@ Documentation for [CannotWaitForTheseOptimisers](https://github.com/MurrellGroup
 ```@autodocs
 Modules = [CannotWaitForTheseOptimisers]
 ```
+
+## Experimental
+
+```@autodocs
+Modules = [CannotWaitForTheseOptimisers.Experimental]
+```
\ No newline at end of file
diff --git a/src/CannotWaitForTheseOptimisers.jl b/src/CannotWaitForTheseOptimisers.jl
index fa5bf9c..8c01925 100644
--- a/src/CannotWaitForTheseOptimisers.jl
+++ b/src/CannotWaitForTheseOptimisers.jl
@@ -5,6 +5,8 @@ import Optimisers: OptimiserChain, AbstractRule, Leaf, adjust, adjust!, _adjust,
 
 include("rules.jl")
 include("adjust.jl")
+include("setup.jl")
+include("Experimental/Experimental.jl")
 
 export Muon, Apollo, NormGrowthCap, GradNormControl, AdaptiveGradNormControl
 
diff --git a/src/Experimental/Experimental.jl b/src/Experimental/Experimental.jl
new file mode 100644
index 0000000..3f447da
--- /dev/null
+++ b/src/Experimental/Experimental.jl
@@ -0,0 +1,13 @@
+module Experimental
+
+include("Muon.jl")
+export Muon
+
+using Base: IdSet
+export IdSet
+
+using Functors: fcollect
+findnodes(pred::Function, x) = filter(pred, fcollect(x))
+export findnodes
+
+end
diff --git a/src/Experimental/Muon.jl b/src/Experimental/Muon.jl
new file mode 100644
index 0000000..db4edf7
--- /dev/null
+++ b/src/Experimental/Muon.jl
@@ -0,0 +1,58 @@
+using MatrixSign
+using Optimisers: AbstractRule, @lazy, @..
+import Optimisers: init, apply!, adjust!
+
+nonfirstdims(x, dims=ndims(x)) = prod(size(x)[2:dims])
+nonfirstdims(x, ::Nothing) = nonfirstdims(x)
+
+"""
+    Muon(η = 0.02, μ = 0.95, λ = 0.01; dims = nothing)
+    Muon(; [eta, mu, lambda, dims])
+
+Muon - MomentUm Orthogonalized by Newton-schulz (https://github.com/KellerJordan/Muon)
+
+Muon internally runs standard SGD-momentum, and then performs an orthogonalization post-processing step,
+in which each 2D parameter's update is replaced with the nearest orthogonal matrix using Newton-Schulz iteration.
+
+# Parameters
+- Learning rate (`η == eta`): Amount by which gradients are discounted before updating the weights
+- Momentum (`μ == mu`): Controls the acceleration of gradient descent in the prominent direction
+- Weight decay (`λ == lambda`): Controls the strength of ``L_2`` regularisation.
+- Keyword `dims`: Dimensions to orthogonalize. If `nothing`, then trailing dimensions get flattened
+  into the second dimension. If `dims < ndims(x)`, remaining dimensions are orthogonalized independently.
+
+Note: Works best with large batch sizes and may not be suitable for fine-tuning.
+In nanoGPT speedrun experiments, Muon is used for the internal layer >2D weights, and AdamW is used for the 1D weights, embeddings, and heads.
+
+`Optimisers.adjust!(optimiser_state, η::Real)` will adjust the fallback optimizer's `eta` to `η * (opt.eta / eta)`, and Muon's `eta` to `η`, preserving their ratio,
+but `Optimisers.adjust!(optimiser, eta = η)` will only adjust Muon's learning rate (allowing you to adjust the fallback optimizer's learning rate separately).
+"""
+@kwdef struct Muon <: AbstractRule
+    eta = 0.02
+    mu = 0.95
+    lambda = 0.01
+    dims = nothing
+end
+
+init(::Muon, x::AbstractArray) = zero(x)
+
+function apply!(
+    (; eta, mu, lambda, dims)::Muon,
+    state, x::AbstractArray{T}, dx
+) where T
+    η, μ, λ = T(eta), T(mu), T(lambda)
+    # update momentum
+    @.. state = μ * state + (1-μ) * dx
+    # Nesterov update fed to msign
+    U = @. μ * state + (1-μ) * dx
+    # orthogonalize
+    Ot = msign!(
+        reshape(U, size(U, 1), nonfirstdims(U, dims), :),
+        steps=5, fused=3)
+    # post shape factor
+    s = √max(1, T(size(Ot, 1) / size(Ot, 2)))
+    dx′ = @lazy η * (Ot * s + λ * x)   # decoupled WD, step will subtract dx′
+    return state, dx′
+end
+
+adjust!(r::Muon, η::Real) = adjust!(r, eta = η)
diff --git a/src/setup.jl b/src/setup.jl
new file mode 100644
index 0000000..af9313a
--- /dev/null
+++ b/src/setup.jl
@@ -0,0 +1,26 @@
+# See https://github.com/FluxML/Optimisers.jl/pull/204
+
+setup(rule::AbstractRule, model) = setup(Returns(rule), model)
+function setup(fun::Function, model)
+  cache = IdDict()
+  tree = _setup(fun, model; cache)
+  isempty(cache) && @warn "setup found no trainable parameters in this model"
+  tree
+end
+
+# _setup is almost fmapstructure, but needs a _trainable_walk, and a cache which ignores numbers etc.
+function _setup(fun::Function, x; cache)
+  haskey(cache, x) && return cache[x]
+  if isnumeric(x)
+    rule = fun(x)::AbstractRule
+    ℓ = Leaf(rule, init(rule, x))
+    if isbits(x)
+      cache[nothing] = nothing  # just to disable the warning
+      ℓ
+    else
+      cache[x] = ℓ
+    end
+  else
+    mapvalue(xᵢ -> _setup(fun, xᵢ; cache), _trainable(x))
+  end
+end
\ No newline at end of file
diff --git a/test/Project.toml b/test/Project.toml
new file mode 100644
index 0000000..b1db398
--- /dev/null
+++ b/test/Project.toml
@@ -0,0 +1,11 @@
+[deps]
+CannotWaitForTheseOptimisers = "16124dda-d9fe-413b-a880-e3f4df3aa341"
+ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
+Functors = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Optimisers = "3bd65402-5787-11e9-1adc-39752487f4e2"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
+Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"