How do I add a mesh in R studio for the X axis?

Hi everyone,

I am new to using Plotly and I need to add a mesh plane on the x-axis. I have got the mesh plane on the z-axis with the following:

Cars Example

my_data <- mtcars
library(plotly)
df <- data.frame(x = my_data$drat, y = my_data$wt, z = my_data$qsec)
planDf <- data.frame(x = rep(range(df$x, na.rm = T), 2), y = rep(range(df$y, na.rm = T), each = 2), z = 20)
plan_df_2 <- data.frame(x = rep(range(df$x, na.rm = T), 2), y = rep(range(df$y, na.rm = T), each = 2), z = 100)

my_data$gear = as.character(my_data$gear)

plot_ly(my_data) %>%
add_markers(x = ~drat, y = ~wt, z = ~qsec, color = ~gear, colors = c(“firebrick”, “forestgreen”, “orange”)) %>%
add_mesh(x = ~x, y = ~y, z = ~z, data = planDf, opacity = 0.3)

however, I want to add another plane at x = 4 but I cannot figure out how to do so - could anyone please help?