diff --git a/NAMESPACE b/NAMESPACE
index 36ae864..1a3658b 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -30,6 +30,10 @@ export(sampleGeomMeam)
 export(sampleGeomMeanApprox)
 export(sampleLongitudinal)
 export(sampleTableCLR)
+importFrom(MASS,mvrnorm)
+importFrom(compositions,acomp)
+importFrom(compositions,ilr)
+importFrom(compositions,ilrInv)
 importFrom(dirmult,rdirichlet)
 importFrom(stats,rbeta)
 importFrom(stats,rnorm)
diff --git a/R/mock-extend.R b/R/mock-extend.R
new file mode 100644
index 0000000..2d19604
--- /dev/null
+++ b/R/mock-extend.R
@@ -0,0 +1,212 @@
+#' Extend a community forward in time with sample-aware naming
+#'
+#' @description Predict forward simulation of a compositional time series
+#' @param init_composition named vector of compositions from previous sample
+#' @param A fitted temporal dynamics matrix
+#' @param Q fitted process covariance matrix
+#' @param alpha fitted overdispersion parameter
+#' @param n_time numeric. Number of future timepoints to simulate
+#' @param read_depth vector or scalar. Sequencing depth per timepoint
+#' @param n_replicates numeric. Number of independent simulation paths
+#' @param sample_name character. Prefix for sample naming
+#' @param start_timepoint numeric. Last observed timepoint index
+#' @param technical_replicate logical. If TRUE, all replicates will have the same observed composition at each timepoint. If FALSE, each replicate will have its own observed composition.
+#' @importFrom compositions ilr acomp ilrInv
+#' @importFrom MASS mvrnorm
+#' @importFrom dirmult rdirichlet
+#'
+
+orrey_extend <- function(
+    init_composition,
+    A,
+    Q,
+    alpha = 10,
+    n_time = 10,
+    read_depth = rep(50000, n_time),
+    n_replicates = 1,
+    sample_name = "sample",
+    start_timepoint = 0,
+    technical_replicate = FALSE
+){
+
+p0 <- init_composition / sum(init_composition)
+K <- length(p0)
+
+if(length(read_depth) == 1){
+    read_depth <- rep(read_depth, n_time)
+}
+n_time <- as.integer(n_time)
+n_replicates <- as.integer(n_replicates)
+stopifnot("read_depth must be a scalar or a vector of length n_time"= length(read_depth) == n_time)
+stopifnot("Q must be a symmetric matrix" = isSymmetric(Q))
+stopifnot("n_time must be a positive integer" = (n_time > 0 & n_time == round(n_time)))
+stopifnot("n_replicates must be a positive integer" = (n_replicates > 0 & n_replicates == round(n_replicates)))
+stopifnot("All eigenvalues of Q must be positive" = all(eigen(Q)$values > 0))
+species_names <- names(p0)
+if (is.null(species_names)) {
+    species_names <- paste0("sp", seq_len(K))
+}
+
+sample_ids <- as.vector(outer(seq_len(max(1, n_replicates)), start_timepoint + seq_len(n_time), FUN = function(r, t) if (n_replicates > 1) paste0(sample_name, "_t", t, "_r", r) else paste0(sample_name, "_t", t)))
+
+n_samples <- length(sample_ids)
+
+
+Z_store <- matrix(
+    NA,
+    nrow = K - 1,
+    ncol = n_samples,
+    dimnames = list(
+        paste0("ilr", seq_len(K - 1)),
+        sample_ids
+    )
+)
+
+P_store <- matrix(
+    NA,
+    nrow = K,
+    ncol = n_samples,
+    dimnames = list(
+        species_names,
+        sample_ids
+    )
+)
+
+Y_store <- matrix(
+    NA,
+    nrow = K,
+    ncol = n_samples,
+    dimnames = list(
+        species_names,
+        sample_ids
+    )
+)
+
+z_prev <- ilr(acomp(p0))
+
+for(i in seq_len(n_time)){
+
+    mu_t <- as.vector(A %*% z_prev)
+
+    z_t <- mvrnorm(
+        n = 1,
+        mu = mu_t,
+        Sigma = Q
+    )
+
+    p_t <- as.vector(ilrInv(z_t))
+    p_t <- p_t / sum(p_t)
+    names(p_t) <- species_names
+
+    z_prev <- z_t
+    theta <- p_t * alpha
+    if (technical_replicate) {
+
+
+    p_obs <- rdirichlet(1, theta)
+    p_obs <- as.vector(p_obs)
+    names(p_obs) <- species_names
+
+    for(r in seq_len(n_replicates)){
+
+        y_t <- as.vector(rmultinom(
+            1,
+            size = read_depth[i],
+            prob = p_obs
+        ))
+        names(y_t) <- species_names
+
+        idx <- (i - 1) * n_replicates + r
+
+        Z_store[, idx] <- z_t
+        P_store[, idx] <- p_t
+        Y_store[, idx] <- y_t    }
+
+} else {
+
+
+    for(r in seq_len(n_replicates)){
+
+        p_obs <- rdirichlet(1, theta)
+        p_obs <- as.vector(p_obs)
+        names(p_obs) <- species_names
+
+        y_t <- as.vector(rmultinom(
+            1,
+            size = read_depth[i],
+            prob = p_obs
+        ))
+        names(y_t) <- species_names
+
+        idx <- (i - 1) * n_replicates + r
+
+        Z_store[, idx] <- z_t
+        P_store[, idx] <- p_t
+        Y_store[, idx] <- y_t    }
+}}
+
+
+
+return(list(
+    sample_ids = sample_ids,
+    true_latent_z = Z_store,
+    true_composition = P_store,
+    observed_counts = Y_store,
+    parameters = list(
+        A = A,
+        Q = Q,
+        alpha = alpha,
+        read_depth = read_depth,
+        sample_name = sample_name,
+        start_timepoint = start_timepoint,
+        species_names = species_names,
+        n_replicates = n_replicates
+    )
+))
+}
+
+#' Generate mock parameters for testing
+#'
+#' @description Generate mock parameters for testing the orrey_extend function.
+#' @param n_features numeric. Number of features in the dataset.
+#' @param persistence numeric. Persistence parameter for the dynamics matrix.
+#' @param interaction_sd numeric. Standard deviation of the interaction terms in the dynamics matrix.
+#' @param individual_sd numeric. Standard deviation of independent species-specific variability.
+#' @param shared_sd numeric. Standard deviation of shared environmental variability.
+#' @param n_factors numeric. Number of latent ecological factors influencing covariance.
+#' @param factor_sd numeric. Standard deviation of latent factor effects.
+
+#'
+#' @return A list containing the mock parameters.
+#'
+mock_parameters <- function(
+    n_features = 10,
+    persistence = 0.95,
+    interaction_sd = 0.01,
+    individual_sd = 0.05,
+    shared_sd = 0.02,
+    n_factors = 3,
+    factor_sd = 0.05
+){
+
+    init <- setNames(runif(n_features), paste0("sp", seq_len(n_features)))
+    init <- init / sum(init)
+
+    D <- n_features - 1
+
+    A <- diag(persistence, D)
+    A <- A + matrix(rnorm(D^2, sd = interaction_sd), D, D)
+    diag(A) <- persistence
+    Q_individual <- diag(individual_sd^2, D)
+
+    u <- rep(1, D)
+    Q_shared <- shared_sd^2 * outer(u, u)
+    L <- matrix(rnorm(D * n_factors, sd = factor_sd), D, n_factors)
+    Q_factor <- L %*% t(L)
+
+    Q <- Q_individual + Q_shared + Q_factor
+
+    Q <- (Q + t(Q)) / 2
+
+    list(init = init, A = A, Q = Q)
+}
\ No newline at end of file
diff --git a/man/mock_parameters.Rd b/man/mock_parameters.Rd
new file mode 100644
index 0000000..afa1b69
--- /dev/null
+++ b/man/mock_parameters.Rd
@@ -0,0 +1,37 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/mock-extend.R
+\name{mock_parameters}
+\alias{mock_parameters}
+\title{Generate mock parameters for testing}
+\usage{
+mock_parameters(
+  n_features = 10,
+  persistence = 0.95,
+  interaction_sd = 0.01,
+  individual_sd = 0.05,
+  shared_sd = 0.02,
+  n_factors = 3,
+  factor_sd = 0.05
+)
+}
+\arguments{
+\item{n_features}{numeric. Number of features in the dataset.}
+
+\item{persistence}{numeric. Persistence parameter for the dynamics matrix.}
+
+\item{interaction_sd}{numeric. Standard deviation of the interaction terms in the dynamics matrix.}
+
+\item{individual_sd}{numeric. Standard deviation of independent species-specific variability.}
+
+\item{shared_sd}{numeric. Standard deviation of shared environmental variability.}
+
+\item{n_factors}{numeric. Number of latent ecological factors influencing covariance.}
+
+\item{factor_sd}{numeric. Standard deviation of latent factor effects.}
+}
+\value{
+A list containing the mock parameters.
+}
+\description{
+Generate mock parameters for testing the orrey_extend function.
+}
diff --git a/man/orrey_extend.Rd b/man/orrey_extend.Rd
new file mode 100644
index 0000000..2fb9579
--- /dev/null
+++ b/man/orrey_extend.Rd
@@ -0,0 +1,43 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/mock-extend.R
+\name{orrey_extend}
+\alias{orrey_extend}
+\title{Extend a community forward in time with sample-aware naming}
+\usage{
+orrey_extend(
+  init_composition,
+  A,
+  Q,
+  alpha = 10,
+  n_time = 10,
+  read_depth = rep(50000, n_time),
+  n_replicates = 1,
+  sample_name = "sample",
+  start_timepoint = 0,
+  technical_replicate = FALSE
+)
+}
+\arguments{
+\item{init_composition}{named vector of compositions from previous sample}
+
+\item{A}{fitted temporal dynamics matrix}
+
+\item{Q}{fitted process covariance matrix}
+
+\item{alpha}{fitted overdispersion parameter}
+
+\item{n_time}{numeric. Number of future timepoints to simulate}
+
+\item{read_depth}{vector or scalar. Sequencing depth per timepoint}
+
+\item{n_replicates}{numeric. Number of independent simulation paths}
+
+\item{sample_name}{character. Prefix for sample naming}
+
+\item{start_timepoint}{numeric. Last observed timepoint index}
+
+\item{technical_replicate}{logical. If TRUE, all replicates will have the same observed composition at each timepoint. If FALSE, each replicate will have its own observed composition.}
+}
+\description{
+Predict forward simulation of a compositional time series
+}