The artist carefully fits two figures into this curved corner, encased with a wooden frame. Their offerings, as mentioned in the title of the artwork, appear to be wheat and something to drink, probably mead or wine. Their poses aim to draw this panel painting with its neighbouring artwork, where series of panels like this are normally all inter-related.
Artist Van Eyck may have passed over some of his work on this panel to assistants in his studio so that he could concentrate fully on the more signficant central panels. His staff were all highly skilled and well trained, so he would have had no qualms in allowing them to complete their supporting panels. In some cases Renaissance artists would produce study sketches for their studio in order to ensure that the artists went in the right direction, artistically.
The artist uses shading and shadows to create a look of sculptured figures, as if made of stone or marble. In reality, these are flat painted portraits, though beautifully done. He sometimes did the same to frames as well, either painting them on by hand or adding considerable more detail than they would normally have.
It is the attention to detail which makes this overall altarpiece such a marvel, with so much to see in every section of each panel. This ensured that he must have had help in order to deliver this reasonably efficiently and inline with agreed timescales.