diff --git a/demultiplex_parse_for_cats.R b/demultiplex_parse_for_cats.R
new file mode 100644
index 0000000..cb134e5
--- /dev/null
+++ b/demultiplex_parse_for_cats.R
@@ -0,0 +1,56 @@
+library(Seurat)
+library(stringr)
+library(dplyr)
+library(purrr)
+library(tidyr)
+library(fs)
+# function definitions
+subset_count_matrix <- function(scmatrix, barcodes) {
+    # helper to call purrr::map
+    scmatrix[, barcodes]
+}
+call_writecounts <- function(sample, counts, features, data_dir) {
+    # write 10x files with some checks
+    # make out and sample paths
+    out_path <- path(data_dir, "out")
+    sample_path <- path(out_path, sample)
+    # create out dir, write10xCounts does not create dirs recursively
+    dir_create(sample_path)
+    # check if row.names (which are unique) are the same that in features.tsv
+    dedup_genes <- make.unique(features$gene_name)
+
+    if (!identical(row.names(counts), dedup_genes)) stop("not the same")
+    Matrix::writeMM(Matrix::t(counts), path(sample_path, "DGE.mtx"))
+    vroom::vroom_write(features, path(sample_path, "all_genes.csv"), delim = ",")
+    vroom::vroom_write(
+        data.frame(bc_wells = colnames(counts), sample = sample),
+        path(sample_path, "cell_metadata.csv"),
+        delim = ','
+    )
+}
+# do stuff
+data_dir <- "./"
+# read data in
+
+mtx <- file.path(data_dir, "DGE.mtx")
+cells <- file.path(data_dir, "cell_metadata.csv")
+features <- file.path(data_dir, "all_genes.csv")
+scdata <- ReadMtx(mtx = mtx, cells = cells, features = features,
+               cell.column = 1, feature.column = 1, cell.sep = ",",
+               feature.sep = ",", skip.cell = 1, skip.feature = 1, mtx.transpose = TRUE)
+
+
+mdata <- vroom::vroom(path(data_dir,  "cell_metadata.csv"))
+features <- vroom::vroom(path(data_dir,"all_genes.csv"))
+# extract the counts per sample to a tibble
+mdata |>
+    select(bc_wells, sample) |>
+    rename(barcodes = bc_wells) |>
+    group_by(sample) |>
+    nest() |>
+    rowwise() |>
+    mutate(counts = purrr::map(data, ~ subset_count_matrix(scdata, .x))) -> matrices
+# write the counts to 10x files
+matrices %>%
+    select(sample, counts) %>%
+    pwalk(call_writecounts, features, data_dir)