diff --git a/.gitmodules b/.gitmodules
index 016d0c0..d1448a0 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -3,5 +3,5 @@
 	url = https://git.vlab.cse.kyutech.ac.jp/stefan/kyupy.git
 	branch = devel
 [submodule "circuits/picorv32"]
-	path = circuits/picorv32
+	path = picorv32
 	url = git@github.com:s-holst/picorv32.git
diff --git a/.python-version b/.python-version
new file mode 100644
index 0000000..e4fba21
--- /dev/null
+++ b/.python-version
@@ -0,0 +1 @@
+3.12
diff --git a/circuits/picorv32 b/circuits/picorv32
deleted file mode 160000
index d438ffd..0000000
--- a/circuits/picorv32
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit d438ffd49054288dc6d025e0a0ad2ae3cc1cfe1f
diff --git a/kyupy b/kyupy
index f0b55ee..c4aecbd 160000
--- a/kyupy
+++ b/kyupy
@@ -1 +1 @@
-Subproject commit f0b55eed271941db16687dbc625a18ef2e96f25d
+Subproject commit c4aecbd6c94e86a18a3a7faab14789e84af61280
diff --git a/main.py b/main.py
new file mode 100755
index 0000000..05247de
--- /dev/null
+++ b/main.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env -S uv run
+
+from pathlib import Path
+from kyupy import verilog
+from kyupy.techlib import SKY130
+
+def path_for(circuit: str):
+    import subprocess
+    return Path(subprocess.check_output(
+        ["nix", "build", "--print-out-paths", "--no-link",
+         f"github:s-holst/benchmark-circuits#{circuit}" ],
+        text=True,
+    ).strip())
+
+def verilog_nl_path_for(circuit: str):
+    return next(path_for(circuit).glob("*/nl/*.nl.v"))
+
+def main():
+    c = verilog.load(verilog_nl_path_for("picorv32-sky130"), tlib=SKY130)
+    c.resolve_tlib_cells(SKY130)
+    for kind, count in sorted(c.stats.items()): print(f'{kind:10s} {count}')
+
+if __name__ == "__main__":
+    main()
diff --git a/picorv32 b/picorv32
new file mode 160000
index 0000000..cf92946
--- /dev/null
+++ b/picorv32
@@ -0,0 +1 @@
+Subproject commit cf92946d63004dc398df307ef44adce5505f65e2
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..17a8ce4
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,16 @@
+[project]
+name = "infield"
+version = "0.1.0"
+description = "Add your description here"
+requires-python = ">=3.12,<3.14"
+dependencies = [
+    "kyupy",
+]
+
+[tool.uv.workspace]
+members = [
+    "kyupy",
+]
+
+[tool.uv.sources]
+kyupy = { workspace = true, editable = true }
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..ea5be98
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,38 @@
+#
+# This file defines a development shell containing:
+#   - hardware synthesis and simulation tools
+#   - riscv32 cross-compiling toolchain
+#
+# Enable this shell by calling 'nix-shell' in the same directory as this file.
+#
+
+let
+    nixpkgs = fetchTarball "https://github.com/NixOS/nixpkgs/tarball/release-25.11";
+    pkgs = (import nixpkgs {}).pkgsCross.riscv32-embedded;
+in
+
+# callPackage is needed due to https://github.com/NixOS/nixpkgs/pull/126844
+pkgs.pkgsStatic.callPackage ({ pkgs }: pkgs.mkShell {
+
+    # these tools run on the build platform, but are configured to target the host platform
+    nativeBuildInputs = with pkgs; [ pkg-config file ];
+
+    # libraries needed for the host platform
+    buildInputs = with pkgs; [ zlib ];
+
+    # tools running on build platform and target the build platform
+    depsBuildBuild = with pkgs; [
+        python3
+        gcc
+        yosys
+        sby
+        nextpnr
+        arachne-pnr
+        icestorm
+        z3
+        boolector
+        yices
+        iverilog
+        verilator
+    ];
+}) {}
\ No newline at end of file