When trying to make a bar graph with m-graph.mkiv and sarith, the command Ssub (string subtract) seems to Sadd instead. An mwe of a bar graph: (data1 is a separate file containing 01 02 02 03) \usemodule[m-graph] \startMPpage[instance=graph] input sarith; draw begingraph(5cm,5cm); gdata("data1", v, path p; augment.p(v1,0); augment.p(v1,v2) augment.p(v1 Sadd "0.4",v2); augment.p(v1 Sadd "0.4",0); gfill p--cycle withcolor .8white; gdraw p--cycle; ); endgraph; \stopMPpage ...which gives bars of width 0.4 starting at abscissa 1 and 2 as expected. To increase the width of the bars to 0.8 and have them centered over 1 and 2, I expect to Ssub from the first two augments: \usemodule[m-graph] \startMPpage[instance=graph] input sarith; draw begingraph(5cm,5cm); gdata("data1", v, path p; augment.p(v1 Ssub "0.4",0); augment.p(v1 Ssub "0.4",v2); augment.p(v1 Sadd "0.4",v2); augment.p(v1 Sadd "0.4",0); gfill p--cycle withcolor .8white; gdraw p--cycle; ); endgraph; \stopMPpage However, the Ssub adds instead and gives a line at 1.4 and 2.4. Compiling the above with mpost or mptopdf gives the desired result(s), but I am curious if this can be resolved so such bar graphs could be made within ConTeXT/METAFUN. Thanks! John