Arranging Plots from TraMineR and seqHMM-CodePudding

I want to plot two sequence distribution plots with the TraMineR package (seqplot(type = 'd')) and below them two Hidden Markov Models which correspond to the sequence plots (those are clusters).

For the reprex, I just use the build in biofam data set. Using layout() produces the desired result up to the third plot. The fourth plot is drawn to a new page, so essentially the bottom right space is left empty, but the first three panes are used accordingly to the layout() specs.

library('seqHMM')
library('TraMineR')

data("biofam")
biofam <- biofam[sample(nrow(biofam),300),]
biofam.lab <- c("Parent", "Left", "Married", "Left Marr",
                "Child", "Left Child", "Left Marr Child", "Divorced")
biofam.seq <- seqdef(biofam, 10:25, labels=biofam.lab)
#>  [>] 8 distinct states appear in the data:
#>      1 = 0
#>      2 = 1
#>      3 = 2
#>      4 = 3
#>      5 = 4
#>      6 = 5
#>      7 = 6
#>      8 = 7
#>  [>] state coding:
#>        [alphabet]  [label]  [long label]
#>      1  0           0        Parent
#>      2  1           1        Left
#>      3  2           2        Married
#>      4  3           3        Left Marr
#>      5  4           4        Child
#>      6  5           5        Left Child
#>      7  6           6        Left Marr Child
#>      8  7           7        Divorced
#>  [>] 300 sequences in the data set
#>  [>] min/max sequence length: 16/16
### Plot the sequence
seqplot(biofam.seq,type='d',with.legend=FALSE)

### Fit a Hidden Markov Model
biofam.hmm <- build_hmm(observations = biofam.seq, n_states = 3)
### Plot the HMM once
plot(biofam.hmm, with.legend=FALSE)
### Use layout to plot two sequence distribution plots and below there HMM
layout(matrix(c(1,2,3,4), ncol = 2, byrow = TRUE))
layout.show(4)


par(cex = 0.65, mar = c(2.5,4.1,2.5,1.5))
### The Sequence plots
seqplot(biofam.seq, type = 'd', with.legend = FALSE, border = NA, ylab = NA)
seqplot(biofam.seq, type = 'd', with.legend = FALSE, border = NA, ylab = NA)
### Change the par() arguments
par(cex = 0.5, mar = c(1.5,3.5,3.5,1.5))
plot(biofam.hmm, with.legend = FALSE, vertex.size = 15)
plot(biofam.hmm, with.legend = FALSE, vertex.size = 15)

^{Created on 2022-11-20 by the}