I have created the following code for a graph in which four fitted lines and corresponding points are plotted. I have problems with the legend. For some reason I cannot find a way to assign the different shapes of the points to a variable name. Also, the colours do not line up with the actual colours in the graph.

```
y1 <- c(1400,1200,1100,1000,900,800)
y2 <- c(1300,1130,1020,970,830,820)
y3 <- c(1340,1230,1120,1070,940,850)
y4 <- c(1290,1150,1040,920,810,800)

df <- data.frame(x,y1,y2,y3,y4)

g <- ggplot(df, aes(x=x), shape="shape") +
  geom_smooth(aes(y=y1), colour="red", method="auto", se=FALSE) + geom_point(aes(y=y1),shape=14) +
  geom_smooth(aes(y=y2), colour="blue", method="auto", se=FALSE) + geom_point(aes(y=y2),shape=8) +
  geom_smooth(aes(y=y3), colour="green", method="auto", se=FALSE) + geom_point(aes(y=y3),shape=6) +
  geom_smooth(aes(y=y4), colour="yellow", method="auto", se=FALSE) + geom_point(aes(y=y4),shape=2) +
  ylab("x") + xlab("y") + labs(title="overview")
  geom_line(aes(y=1000), linetype = "dashed")
  theme_light() +
  theme(plot.title = element_text(color="black", size=12, face="italic", hjust = 0.5)) +
  scale_shape_binned(name="Value g", values=c(y1="14",y2="8",y3="6",y4="2"))

print(g)

```

I am wondering why the colours don't match up and how I can construct such a legend that it is clear which shape corresponds to which variable name.